A sheet separator including a separation roller and a separation pad having a separation surface facing an outer circumferential surface of the separation roller in a nip position between the separation surface and the outer circumferential surface, the separation surface including a first surface disposed upstream relative to the nip position in a first direction perpendicular to the axis, the first surface including a curved surface that is curved to become closer to the axis in a direction toward the nip position from an upstream end portion of the separation surface in the first direction, and a second surface disposed downstream relative to the nip position in the first direction, the second surface flatly extending along a second direction parallel to the axis.