PROBLEM TO BE SOLVED: To provide a diaper for pets, capable of flexibly cope with the pets having different body shapes and sizes, and also reducing the occurrence of leak. SOLUTION: This diaper for the pet is equipped with a body part constituting the diaper body, leg openings for inserting rear legs of the pet, a waist opening positioned at the circumference of the trunk of the pet, and an absorbing body installed at the body part and absorbing the excrement of the pet. Also, in the body part, by installing a cut from the waist opening part to its inside in the zone positioned at the back side of the pet, the body part is separated into two by left and right to form first and second separated sheets. Then, it is constituted to encircle so as to nip the tail of the pet with the first and second sheets. No passing through hole is installed on the halfway of the cut.
