To provide a sauna bathroom having sufficient decorative properties directly linked to the attraction of customers, enhanced in heat retaining property to contribute to energy saving and achieving the enhancement of effect.

The side wall part 1 for constituting the inner wall surface of a sauna room is constituted so that a skeleton frame 13 formed as a framework having a required shape is provided adjacent to a concrete foundation part 12 vertically provided to partition the room and amethyst C is embedded in a sauna wall foundation part 14 formed by cast concrete or the skeleton frame 13 so as to be exposed from the wall surface of the sauna wall foundation part 14. A ceiling wall part 2 is formed by bonding amethyst C to one plane of a refractory slate plate 211 to form a quartz plate 21 and this quartz plate 21 is provided so as to leave a required interval from a ceiling foundation part 24 so that the surface of amethyst C is turned downward.