A receptacle for animal excrement mainly comprises a fixing device and an excrement bag. The fixing device comprises a fixing seat provided with a through hole, an elastic rope having two ends connected to the fixing seat, a movable fastener that is fastened on the elastic rope and capable of being arbitrarily moved and positioned thereon, and two bridging ropes that have individual ends connected to the fixing seat and free ends capable of being connected to each other. The excrement bag is detachably combined to the fixing seat of the fixing object to receive animal excrements. As such, since the movable fastener can be arbitrarily positioned on the elastic rope, deformation that occurs on the elastic rope at locations close to the excrement bag can be alleviated, thereby maintaining precise alignment of the excrement bag with respect to an excretory site of the animal.