To provide a hot water level setting device capable of arbitrarily setting a hot water level corresponding to a physique of a person taking a bath to keep the hot water level in a bathtub constant, and coping with failure of the device.

This hot water level setting device is composed of an overflow hot water level setting means A for keeping a set hot water level by draining hot water when the hot water level is over the set hot water level, a pressure setting means B for keeping the set hot water level by a pressure sensor portion 8, and a bathtub body 9. The overflow hot water level setting means A and the pressure setting means B are disposed outside of the bathtub body 9 through a bathtub bottom portion 95 side and a pipe.