To provide a disposable diaper for pets, capable of effectively preventing leakage of excrement. A disposable diaper for pets, in which part of a crotch area (120) stands up as a result of the contraction of an expanding/contracting elastic member (600), and a standing-up section (700) is formed, said disposable diaper for pets having: a rear-side waist area (130)； a stomach-side waist area (110)； the crotch area (120)； both end sections (130A, 110A) in the diaper longitudinal direction； both end sections (100A) in the diaper longitude-intersecting direction； a tail insertion opening (190)； an absorbent core (200)； an attachment section (300) provided in the stomach-side waist area (110)； an attachment area (900) that receives the attachment section (300)； and the expanding/contracting elastic member (600) arranged the diaper longitudinal direction.
