A cover member (4, 44, 54) for a pet toilet sheet, to be mounted on a pet toilet sheet that absorbs excreted fluid from a pet, and serving to press the toilet sheet in a partially covered state, the cover member (4, 44, 54) comprising a base section having a first end and a second end located in a reciprocal direction relative to the first end in a horizontal direction, and an edge section provided along an edge of the first end, wherein: the base section has, on a top surface, an inclined surface that gradually declines from the first end toward the second end, to allow movement of excreted fluid from the pet toward the toilet sheet, the inclined surface having a first inclined section that is inclined from the edge of the first end toward the second end, the edge of the first end being connected to the edge section, and a second inclined section located more toward the second end side than the first inclined section, with its first end side connected to the first inclined section and inclined to an edge of the second end, the second inclined section having a greater inclination than the first inclined section, and a connecting section between the first inclined section and the second inclined section being curved in a convex manner upward from the first end side toward the second end side, while a distance from an end portion of the second inclined section on the first end side to a second end edge is smaller than a distance from a first end edge of the first inclined section to an end portion on the second end side, wherein the edge section has an inclined surface on the top surface side, that gradually declines as it recedes from the first end of the base section, characterized in that the cover member is configured to be mounted on a pet toilet sheet that is spread over a floor surface, and the height of the cover member, at a location where a height in a vertical direction of the cover member (4, 44, 54) is greatest, is 9 to 37% of a distance from the edge of the second end of the base section to the edge of the base section on a side opposite the first end at a nearest portion of the edge section. the base section has, on a top surface, an inclined surface that gradually declines from the first end toward the second end, to allow movement of excreted fluid from the pet toward the toilet sheet, the inclined surface having a first inclined section that is inclined from the edge of the first end toward the second end, the edge of the first end being connected to the edge section, and a second inclined section located more toward the second end side than the first inclined section, with its first end side connected to the first inclined section and inclined to an edge of the second end, the second inclined section having a greater inclination than the first inclined section, and a connecting section between the first inclined section and the second inclined section being curved in a convex manner upward from the first end side toward the second end side, while a distance from an end portion of the second inclined section on the first end side to a second end edge is smaller than a distance from a first end edge of the first inclined section to an end portion on the second end side, wherein the edge section has an inclined surface on the top surface side, that gradually declines as it recedes from the first end of the base section, characterized in that the cover member is configured to be mounted on a pet toilet sheet that is spread over a floor surface, and the height of the cover member, at a location where a height in a vertical direction of the cover member (4, 44, 54) is greatest, is 9 to 37% of a distance from the edge of the second end of the base section to the edge of the base section on a side opposite the first end at a nearest portion of the edge section.