PURPOSE: To obtain a large and free glass space irrespective of the structure of a building by installing the bathroom composition member in such a way that it is extruded to the outside from a building main body, and by providing an exterior wall which has at least one face of glass wall surface on the bathroom composition member.

CONSTITUTION: A bathroom composition member 2 is installed in contact with a building main member 1, and is extruded to the outside of the building main member 2, adjacent to the side thereof. An exterior wall 4, and a roof 5 are provided on the bathroom composition member 2, independently with the building main body 1, while a graded wash place 6, a bath tub 7, and an exit 8 are further provided inside. At least one face of the exterior wall 4 of the bathroom composition member 2 is glass wall surface 3. A dome-shaped skylight 9 is provided on the roof 5 of the bathroom composition member 2, and a ringged lighting fixture 12 is provided around the skylight 9. An outside appliance 11 such as a hot water supplyer 11a and a jet pump 11b, is preliminarily installed under the floor in the vicinity of the bath tub, or on the space between each column 13, in a factory. Construction and maintenance can thus be facilitated.