A support sheet for a photographic printing sheet having enhanced anti-fogging and anti-yellowing properties comprises a pulp paper substrate sheet, a front coating layer formed on a front surface of the substrate sheet and comprising a cured resinous material produced from electron beam-curable unsaturated organic compound by an electron beam irradiation thereto and mixed with a white pigment, and a back coating layer formed on a back surface of the substrate sheet and comprising a film-forming synthetic resinous material, in which magnesium hydroxide is contained, as an anti-fogging agent, in the substrate sheet.