To provide an air suction structure of a unit bath provided with an air-bubble bathtub whose suction port is not directly seen from the person who is taking a bath, and also by which the air cutting sound to be transmitted to a person who is taking a bath can be reduced.

A bathtub 5 is arranged on a waterproofing pan 2, and an air pump 6 is arranged on the rear side of the ceiling panel 4, and the discharge port 6a of the air pump 6 and the bottom part of the bathtub are connected by an air supply pipe 7, and the suction port 8a of an air suction pipe 8 connected to the air pump 6 is communicated with the inside A of the unit chamber, so that the suction port 8a is faced to the space Aa surrounded by a wall surface 14a forming a unit bath, the bathtub 5, and an apron 16, and the apron 16 is detachably provided.