A clean and refreshing dry sauna using natural wood. The scent of the wood is pleasant, and the space inspired by fireflies allows you to sweat thoroughly in a calm environment. The high-temperature setting promotes sweating and warms you from the core. After the sauna, a cold plunge bath using the source spring and an outdoor air bath space where you can feel the mountain breeze await, offering a refreshing relaxation experience. Despite being attached to a roadside station, you can enjoy an authentic sauna experience.

A luxurious cold plunge bath using the hot spring's source spring. The moderate coldness comfortably cools down your body heated in the sauna. The alkaline source spring is gentle on the skin, with a crisp coldness that also feels soft. The flow allows you to enter immediately after leaving the Hotaru Sauna, leading smoothly to relaxation. The smooth texture unique to the source spring is a distinctive feature.