An approximately cylindrical central core for cleaning sponge roller having an axially extending internal hole and multiple small holes realizing communication from the internal hole to the circumferential external surface. The central core for cleaning sponge roller is characterized in that the external surface of the central core is provided in the circumferential direction with multiple axially slender projections and that the projections each has an axial section viewed from a direction perpendicular to the axial direction that is not flat.