Gunma · Japan's #1 Onsen Prefecture / 群馬 / 日本一の温泉県、湯量・歴史・名所すべて揃う

Gunma Onsen Guide

Top hot springs, ryokan, and day-use baths in Gunma — bilingual guide for travelers.

群馬のおすすめ温泉地・温泉宿・日帰り温泉を厳選紹介。

No prefecture is more synonymous with onsen than Gunma. Kusatsu — one of the "Three Famous Springs of Japan" praised by the scholar Hayashi Razan — has topped the national onsen popularity ranking for more than two decades, its central "Yubatake" pouring out 4,000 litres a minute of fiercely acidic water. Ikaho climbs a mountainside on 365 stone steps lined with Meiji-era inns; Manza, at 1,800m, is among the highest hot-spring resorts in Japan, with some of its richest sulfur; Minakami pairs gorge foliage with whitewater rafting; and Shima keeps the wooden inn often cited as an inspiration for "Spirited Away." Together they distil everything 1,300 years of Japanese onsen culture has to offer.

温泉といえば群馬、というほど名実ともに日本一の温泉県です。儒学者・林羅山が「天下の三名泉」に挙げた草津は、20年以上も人気温泉地ランキングの首位に立ち、中心の「湯畑」は毎分4,000リットルの強い酸性泉を噴き上げます。伊香保は365段の石段に明治の宿が連なる坂の街、万座は標高1,800m・日本でも有数の高所で最も濃い硫黄泉のひとつ、水上は渓谷の紅葉とラフティング、四万は「千と千尋」のモデルとも言われる木造の宿を守ります。これらが、1,300年の日本の温泉文化のすべてを凝縮しています。

5 Top Onsen in Gunma

Where to soak

群馬のおすすめ温泉地・温泉宿 5選

Kusatsu Onsen (草津温泉)01

Kusatsu Onsen

草津温泉

Japan's #1 onsen for 20+ consecutive years

20年連続日本一、湯量・効能すべて最高峰

SpringStrong acidic chloride sulfur spring (pH 2.1)酸性・含硫黄・塩化物泉(pH2.1)
Fromfrom ¥16,000 / night
SourceFree-flow (kakenagashi) per public info/ 源泉かけ流し(公式情報)

Kusatsu has topped Japan's onsen popularity ranking for more than twenty years running, and the Edo-era scholar Hayashi Razan ranked it among the "Three Famous Springs of Japan," with Arima and Gero. At its heart steams the "Yubatake" (hot-water field), a great wooden cascade where some 4,000 litres a minute of fiercely acidic water (around pH 2) cool on their way to the baths — lit up at night, it is the town's unforgettable image. The strong, naturally antibacterial water was said in an old rhyme to "cure everything but lovesickness," and the traditional "Yumomi," a song-and-paddle ritual that cools the source, survives as a live performance at the Netsu-no-Yu hall.

  • #1 in Japan onsen ranking for 20+ years straight
  • Iconic "Yubatake" wooden cascade at town center
  • Traditional "Yumomi" performance is a cultural heritage

Hours and prices vary — always confirm on the official site before visiting.
営業時間・料金は変動するため、必ず公式サイトでご確認ください。

Ikaho Onsen (伊香保温泉)02

Ikaho Onsen

伊香保温泉

365 stone steps lined with Meiji-era ryokan

365段の石段街、明治ロマン漂う湯の街

SpringIron-bearing sulfate / metahydrocarbonate spring硫酸塩泉・メタケイ酸泉(含鉄)
Fromfrom ¥15,000 / night
SourceFree-flow (kakenagashi) per public info/ 源泉かけ流し(公式情報)

Ikaho climbs the flank of Mt. Haruna on its famous "Ishidan-gai," a stone stairway of exactly 365 steps — one for each day of the year — lined the whole way with old wooden ryokan, craft shops, and the steaming-bun stalls of a town that claims to have invented the onsen-manju (the original, Katsugetsudo, dates to 1910). At the top stands Ikaho Shrine, the source. Two waters flow here: the iron-rich "Kogane-no-Yu" (Golden Bath), which turns ochre as it meets the air, and the clear "Shirogane-no-Yu." Sung of as far back as the Manyoshu and made nationally famous by Tokutomi Roka's 1898 novel "Hototogisu," Ikaho is pure Meiji romance.

  • Iconic 365-step "Ishidan-gai" street
  • "Kogane-no-Yu" (Golden Bath) iron-rich ochre water
  • Pair with Hara Museum ARC + Lake Haruna

Hours and prices vary — always confirm on the official site before visiting.
営業時間・料金は変動するため、必ず公式サイトでご確認ください。

Manza Onsen (万座温泉)03

Manza Onsen

万座温泉

Sky-high sulfur onsen at 1,800m elevation

標高1800m、雲上の硫黄泉

SpringAcidic sulfur spring (highest H₂S in Japan)酸性・含硫黄泉(日本一の硫化水素含有)
Fromfrom ¥14,000 / night
SourceFree-flow (kakenagashi) per public info/ 源泉かけ流し(公式情報)

Manza sits at 1,800m on the slopes of Mt. Kusatsu-Shirane, one of the highest hot-spring resorts open all year in Japan. Its milky, intensely sulfurous water is reckoned among the richest in the country — some twenty different sources steam up around the resort, and the "Karafuki" vent roars white plumes nearby. Open-air baths look out over alpine meadows of flowers in summer and a world of snow in winter. The Manza ski runs are right at the door, and on a clear night, far above the city lights, the stars are extraordinary.

  • One of Japan's highest onsen resorts (1,800m)
  • Said to have Japan's richest sulfur content
  • Direct ski-in/ski-out resort access

Note: The Shirane Volcano Route is closed in winter. From November to April, access via Kusatsu side road only.白根山ルートは冬季閉鎖。11〜4月は草津側からのアクセスのみ。

Hours and prices vary — always confirm on the official site before visiting.
営業時間・料金は変動するため、必ず公式サイトでご確認ください。

Minakami Onsen-kyo (水上温泉郷)04

Minakami Onsen-kyo

水上温泉郷

Riverside foliage + adventure sports playground

渓谷紅葉とアウトドアスポーツの聖地

SpringSodium chloride / sulfate spring塩化物泉・硫酸塩泉
Fromfrom ¥13,000 / night
SourceFree-flow (kakenagashi) per public info/ 源泉かけ流し(公式情報)

Minakami gathers some eighteen hot-spring hamlets along the headwaters of the Tone River, beneath the great wall of Mt. Tanigawa. The Suwa-kyo gorge blazes with maples in mid-October, one of the finest foliage spots in Kanto, but Minakami is best known today as Japan's premier whitewater base — its spring snowmelt rapids draw rafters from across the country, alongside canyoning, bungee jumping, and rides behind the SL Minakami steam locomotive. Adventure by day, a riverside soak by night, all just 80 minutes from Tokyo on the Joetsu Shinkansen.

  • 18 onsen sub-towns along the Tone River
  • Suwa-kyo Gorge — top Kanto foliage spot
  • Japan's #1 rafting + outdoor adventure base

Hours and prices vary — always confirm on the official site before visiting.
営業時間・料金は変動するため、必ず公式サイトでご確認ください。

Shima Onsen (四万温泉)05

Shima Onsen

四万温泉

Showa-era ryokan said to inspire "Spirited Away"

千と千尋の神隠しのモデル説、昭和ロマン温泉

SpringSodium calcium chloride sulfate spring塩化物・硫酸塩泉(ナトリウム・カルシウム)
Fromfrom ¥14,000 / night
SourceFree-flow (kakenagashi) per public info/ 源泉かけ流し(公式情報)

Shima is famed for the Sekizenkan, whose main building, raised in 1691, is recognised as the oldest surviving wooden hot-spring-inn building in Japan; its lantern-lit red bridge is one of the places Hayao Miyazaki himself has named as an image-source for the "Aburaya" bathhouse in "Spirited Away." The name "Shima" means "forty thousand," from a legend that the waters soothe forty thousand ills, and in 1954 Shima was named — with Sukayu and Nikko Yumoto — one of Japan's first three National Health-Resort Onsen. Tucked into a quiet beech-forest valley far from the crowds, it is the most atmospheric of all the Gunma springs.

  • Sekizenkan Honkan — Japan's oldest hot-spring inn building (1691)
  • Red-bridge view often cited as "Spirited Away" inspiration
  • Tranquil beech-forest valley setting

Hours and prices vary — always confirm on the official site before visiting.
営業時間・料金は変動するため、必ず公式サイトでご確認ください。

Insider Tips for Gunma

Know before you go

群馬の旅で知っておきたい5つのこと

See Kusatsu Yumomi Performance

草津の湯もみショーを見る

The traditional water-cooling performance at "Netsu-no-Yu" runs several times daily (check the official schedule). Performers in matching costumes paddle the 51°C source water with long wooden boards while singing folk songs. Bookable on-site — get there 30 min early for front-row seats.

草津「熱乃湯」での湯もみショーは1日数回開催(回数・料金は公式サイトで確認)。揃いの法被で51℃の源泉を木の板で叩いて冷ます伝統儀式と民謡。前列を取るなら30分前到着。

Ikaho Steps + Onsen Manju

伊香保の石段とお饅頭

Walk all 365 stone steps from bottom to top, stopping at the famous onsen manju (steamed buns) shops along the way. "Katsumizu-do" is the original, founded 1910. Top is Ikaho Shrine; on the way down, try the public Ishidan-no-Yu bath (¥410).

伊香保石段を365段、ふもとから頂上の伊香保神社まで歩く。温泉饅頭発祥の「勝月堂」(1910年創業)など老舗が並ぶ。下りで「石段の湯」(410円)に立ち寄り。

Visit Manza Only in Operating Season

万座は営業期間を確認する

Many Manza ryokan have full-year operations, but the iconic Shirane Volcano Route closes November–April. In winter, access is via the Kusatsu side road only — confirm with your ryokan about shuttle service.

万座の宿は通年営業が多いが、白根山ルートは11〜4月閉鎖。冬季は草津側からのみアクセス。送迎バスの有無を宿に確認を。

Photograph Sekizenkan at Dusk

積善館は黄昏時を狙う

The red bridge and Sekizenkan facade photograph best in the "blue hour" just before sunset, when the warm interior lights start glowing. Even non-guests can walk to the bridge for photos — please respect operating hours and quiet.

積善館の赤い橋と本館は日没直前の「青のマジックアワー」が絶景。客でなくとも橋まで歩いて撮影可能(営業時間・静粛に配慮を)。

Pair Minakami with Adventure

水上はアウトドアと組み合わせる

April–November is rafting season on the Tone River — class 3–4 rapids, suitable for first-timers. Many ryokan offer rafting + onsen day packages. Combine with bungee jump or canyoning for a high-octane Gunma trip.

水上のラフティングは4〜11月。利根川の急流(クラス3〜4)は初心者OK。「ラフティング+宿泊」パックを提供する宿も多数。バンジー・キャニオニングと合わせて。

Travel Essentials

Plan your trip

旅の準備

Book a Ryokan

Use major Japanese travel platforms to find ryokan with private open-air baths, tattoo-friendly facilities, or vegan kaiseki meals.

eSIM & WiFi

Most onsen towns have spotty 4G coverage. A Japan eSIM or pocket WiFi keeps Google Maps and translation apps running smoothly.

Getting There

See each onsen listing above for access details. Most Gunma onsen towns are reachable by JR trains, limited express, or highway bus; for remote springs, a rental car gives the most flexibility.

FAQ

Common questions

よくある質問

Is Kusatsu really the best onsen in Japan?草津は本当に日本一?

It tops the Nikkei poll consistently for spring quality and atmosphere. The acidic waters are among Japan's strongest natural antibacterials. That said, "best" depends on what you value — Kusatsu has crowds. Quieter alternatives within Gunma include Shima and Sawatari.

日経新聞「温泉地ランキング」では泉質・雰囲気で常に首位。強酸性の殺菌力は日本屈指。ただし「一番」は好み次第で、混雑を避けたければ四万・沢渡なども群馬の良湯。

How long should I stay in Gunma?群馬には何泊くらい?

Minimum 2 nights: 1 night Kusatsu + 1 night Ikaho or Shima covers the highlights. With 3+ nights, add Minakami (adventure) or Manza (sulfur baths). A full 5-day Gunma onsen tour is one of Japan's best onsen pilgrimages.

最低2泊(草津+伊香保 or 四万)が王道。3泊以上なら水上(アウトドア)or 万座(硫黄泉)を追加。5日あれば群馬温泉巡礼の決定版。

When is the worst time to visit?群馬温泉旅行を避けるべき時期は?

Golden Week (late April–early May), Obon (mid-August), and weekends during peak foliage (mid-late October) book out completely. Kusatsu and Ikaho are especially congested. Weekdays year-round or shoulder seasons (June, September, November) are ideal.

GW・お盆・紅葉週末(10月中下旬)は満室・混雑。草津・伊香保は特に。狙い目は通年の平日 or 6月・9月・11月中旬。

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関東地方の他の県も見る

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