To provide a disposable diaper for pets that fits well around the waist of the pet. A disposable diaper for pets, comprising: a back-side waist area (130)； a stomach-side waist area (110)； a crotch area (120)； both end sections (130A, 110A) in the diaper longitudinal direction； both end sections (120A) in the diaper longitude-intersecting direction； a tail insertion opening (190)； an absorbent core (200)； an area (170) not having the absorbent core arranged therein； an attachment section (300) provided in the stomach-side waist area (110)； an attachment area (900) that accepts the attachment section (300)； an expandable/contractible elastic member (400) for legs, arranged, in an extended state, in a prescribed area in the diaper longitudinal direction, between the absorbent core (200) and an end section (100A) in the diaper longitude-intersecting direction； a leg gather (410) formed by the contraction of the expandable/contractible elastic member (400) for legs； an expandable/ contractible elastic member (500) for the waist, arranged, in an extended state, in the area not having the absorbent core arranged therein, in the diaper longitude-intersecting direction； and a contraction force intersecting area (180) in which the contracting force of the expandable/ contractible elastic member (400) for legs and the expansion/contraction force of the expandable/ contractible elastic member (500) for the waist intersect.
