The present invention provides an absorbent article for animals which is less likely to become detached from an animal body, properly fits the crotch of the animal, and thereby is capable of preventing leakage of excreta. This absorbent article (1) for animals is provided with: a support body part (2) which is detachably worn around the waist including the back and belly of the animal; and an absorbent main body part (3) which is disposed along the back, crotch and belly of the animal and is detachably engaged with and fixed to the support body part (2). When viewed in a planar view in an unfolded state, the absorbent main body part (3) is provided with: an engagement part (38) which is disposed on at least one of end parts which are located at both longitudinal ends; an absorbent body (33); a tail opening part (39); and elastic members (36) which impart a longitudinal contractive force to the absorbent main body part (3). The elastic members (36) are disposed on both widthwise outer sides of the absorbent bo
