Fuigo Onsen is a secluded single-inn hot spring nestled along the Kawata River gorge at the foot of Mount Takakoe (1,133m) in Yamakawa Town, Yoshinogawa City, Tokushima Prefecture. It opened in 1972 as a municipally operated facility utilizing mineral spring water that naturally seeps from the former Takakoe Copper Mine, once the largest copper mine in Tokushima Prefecture. The name Fuigo derives from a suspension bridge called Fuigo-bashi that was built for miners commuting to the Nagoshi Mine across the river during the Meiji era, where bellows (fuigo) were used for ore smelting. The massive schist rock formations flanking the bridge are designated as a National Natural Monument.

The spring water is classified as a green vitriol iron spring (simple cold mineral spring) with a source temperature of 15.4 degrees Celsius, heated for bathing use. The water is colorless, transparent, and odorless, and is known as an exceptionally rare iron-containing spring in Shikoku. The flow rate is 214 liters per minute, with the mineral water piped from the naturally seeping mine site. Therapeutic indications include neuralgia, muscle pain, joint pain, chronic rheumatism, fatigue recovery, cold sensitivity, and athlete''s foot.

The facility features rock baths and tiled baths in the main bathhouse, complemented by a sauna, jacuzzi, and waterfall shower. The large windows of the bathhouse offer views of the vermilion-painted Takakoe Bridge and the copper-tinted green waters of the Kawata River below. The men''s bath includes an outdoor cold water bath and open-air relaxation area. The on-site restaurant serves local cuisine prepared with seasonal Tokushima ingredients. Accommodation consists of six rooms including Japanese-style and Japanese-Western rooms, with rates starting from 6,600 yen for lodging only. Day-trip bathing is 600 yen for adults and 300 yen for children.