A bidet includes: a bidet body part; an operating part; and a power supply part. The operating part includes: an outer housing having a first space formed therein; and a cover covering the opening of the outer housing and being detachably coupled to the outer housing. The power supply part includes: an inner housing, provided in the first space of the outer housing, which has, therein, a second space that is smaller than the first space, and has a first guide member slantedly formed on one side thereof; a battery cartridge, provided in the second space of the inner housing, which has, on the outer surface thereof, a second guide member coupled to the first guide member, and is exposed to the outside with respect to the inner housing according to the second guide member position relative to the first guide member; and a battery in the battery cartridge.