A low-profile unsaturated polyester resin composition, consisting essentially of (A) an unsaturated polyester, (B) a monomer copolymerizable with the unsaturated polyester, and (C) an A-B type block copolymer comprising an A segment which is a product using vinyl acetate and butyl acrylate as raw materials and a B segment which is a product solely of styrene or a product using styrene and a monomer copolymerizable with styrene as raw materials.