An absorbent sheet for pets used for a pet toilet, the pet toilet including a sheet accommodating portion configured to accommodate the absorbent sheet in a space surrounded by a bottom portion and side wall portions standing from the bottom portion, and an excretion receiving portion configured to receive excretions above the sheet accommodating portion, and guide the excretions to the sheet accommodating portion, the absorbent sheet comprising: a topsheet arranged on a top side of the absorbent sheet and having fibers; a backsheet arranged on a back side of the absorbent sheet; an absorber provided between the topsheet and the backsheet; a central region in which the absorber is arranged in plan view, side regions which extend outside the central region in the plan view and in which the topsheet is arranged without the absorber in the plan view, wherein the topsheet has a first surface and a second surface opposite to the first surface, joining portions which join the topsheet and the backsheet are provided in the side regions, and in the side regions, a fiber density of a region on a side of the first surface in the topsheet is lower than a fiber density of a region on a side of the second surface in the topsheet, and a surface roughness of the first surface of the topsheet is higher than a surface roughness of the second surface of the topsheet. the absorbent sheet has a thickness direction, a first direction perpendicular to the thickness direction, and a second direction perpendicular to the thickness direction and the first direction, a length of the absorbent sheet in the first direction is longer than a length of the absorbent sheet in the second direction, the side regions are provided over an entire region of the absorbent sheet in the first direction on both sides of the central region in the second direction, and the topsheet has more fibers oriented along the second direction than fibers oriented along the first direction. a topsheet arranged on a top side of the absorbent sheet and having fibers; a backsheet arranged on a back side of the absorbent sheet; an absorber provided between the topsheet and the backsheet; a central region in which the absorber is arranged in plan view, side regions which extend outside the central region in the plan view and in which the topsheet is arranged without the absorber in the plan view, wherein the topsheet has a first surface and a second surface opposite to the first surface, joining portions which join the topsheet and the backsheet are provided in the side regions, and in the side regions, a fiber density of a region on a side of the first surface in the topsheet is lower than a fiber density of a region on a side of the second surface in the topsheet, and a surface roughness of the first surface of the topsheet is higher than a surface roughness of the second surface of the topsheet. the absorbent sheet has a thickness direction, a first direction perpendicular to the thickness direction, and a second direction perpendicular to the thickness direction and the first direction, a length of the absorbent sheet in the first direction is longer than a length of the absorbent sheet in the second direction, the side regions are provided over an entire region of the absorbent sheet in the first direction on both sides of the central region in the second direction, and the topsheet has more fibers oriented along the second direction than fibers oriented along the first direction.