A radiation shielding material of a composition containing a polymer comprising (A) at least one essential monomer selected from the group consisting of alkyl methacrylate having 1 - 4 carbon atoms in an alkyl group, hydroxyalkyl acrylate, hydroxyalkyl methacrylate and styrene and (B) lead acrylate or lead methacrylate, and a lead carboxylate represented by the general formula: (RCOO).sub.a Pb, a being an integer equal to the valency of lead and R representing a saturated or unsaturated hydrocarbon residue having 5 - 20 carbon atoms, wherein the ratio x (% by weight) of the lead acrylate or lead methacrylate to the total constituent monomer in the polymer and the compounding ratio y (parts by weight) of the lead carboxylate to 100 parts by weight of said total monomer in said composition satisfy any one of the following three formulas I, II and III:200.gtoreq.y.gtoreq.2, where 9.ltoreq.x.ltoreq.30 (I)200.gtoreq.y.gtoreq.2/5(x - 30)+ 2, where 30.ltoreq.x.ltoreq.75(II) and200.gtoreq.y.gtoreq.-9/10(x - 75) + 20, where 75.ltoreq.x.ltoreq.95(III).