An animal litter box having a longitudinal direction, a lateral direction, and a height direction, the animal litter box comprising: an inner space that is a space where an animal performs excretion, the inner space being a space that is surrounded by at least a bottom surface and one or more wall portions, the bottom surface receiving excrement, the wall portion rising in the height direction from a periphery of the bottom surface; and an absorbent-body arrangement portion for arranging of an absorbent body that absorbs excrement, the absorbent-body arrangement portion being provided below the inner space in the height direction, at least one of the wall portions in the longitudinal direction having a notch that serves as an entrance/exit of the inner space, a longitudinal central position of the notch being eccentric on an other side with respect to the longitudinal central position of the inner space, the notch and the absorbent-body arrangement portion being at least partially overlapped with each other in the longitudinal direction, wherein a shape of the bottom surface is in a rectangle in which a length in the longitudinal direction is longer than a length in the lateral direction, characterized in that a longitudinal central position of the inner space is located shifted from a longitudinal central position of the absorbent body arrangement portion, and the longitudinal central position of the absorbent body arrangement portion being eccentric on another side with respect to the longitudinal central position of the inner space. an inner space that is a space where an animal performs excretion, the inner space being a space that is surrounded by at least a bottom surface and one or more wall portions, the bottom surface receiving excrement, the wall portion rising in the height direction from a periphery of the bottom surface; and the inner space being a space that is surrounded by at least a bottom surface and one or more wall portions, the bottom surface receiving excrement, the wall portion rising in the height direction from a periphery of the bottom surface; and an absorbent-body arrangement portion for arranging of an absorbent body that absorbs excrement, the absorbent-body arrangement portion being provided below the inner space in the height direction, at least one of the wall portions in the longitudinal direction having a notch that serves as an entrance/exit of the inner space, the absorbent-body arrangement portion being provided below the inner space in the height direction, at least one of the wall portions in the longitudinal direction having a notch that serves as an entrance/exit of the inner space, a longitudinal central position of the notch being eccentric on an other side with respect to the longitudinal central position of the inner space, the notch and the absorbent-body arrangement portion being at least partially overlapped with each other in the longitudinal direction, wherein a shape of the bottom surface is in a rectangle in which a length in the longitudinal direction is longer than a length in the lateral direction, characterized in that a longitudinal central position of the inner space is located shifted from a longitudinal central position of the absorbent body arrangement portion, and the longitudinal central position of the absorbent body arrangement portion being eccentric on another side with respect to the longitudinal central position of the inner space.