To provide a treatment apparatus with a bathtub for pets which facilitates treatment of pets and suppresses excess water use.

The treatment apparatus with a bathtub comprises a main unit 2 having a bathtub 4 and an examination table 27 arranged detachably on the main unit 2 so as to block the upper opening of the bathtub 4. The bathtub 4 is formed in such a way that the cross-sectional area of the lower part 7 of the bathtub is smaller than that of the upper part 6 of the bathtub to form a catching part 10 inside. A bottom raising plate 5 with a plurality of holes is arranged on the catching part 10 to divide the bathtub into the upper part 6 and the lower part 7. With such a configuration, the volume of the lower part 7 of the bathtub is reduced compared to that of the upper part 6.