PURPOSE: To provide the chair for a bath unit in which a washing place for washing the body in a seated state can be secured in the outside of a bathtub, even in a small-sized bath unit into which a toilet is integrated.

CONSTITUTION: On a stool 21 of a toilet positioned in a bath unit, the lower side plate part 11 of a chair main body 10 is mounted, a projecting part 14 provided on the lower face of the lower side plate part 11 is fitted into the inside peripheral part of the stool 21, and by the upper side plate part 12 of the chair main body 10, a seating part on which a user can be seated is constituted.