PURPOSE:To obtain the titled composition having extremely excellent mechanical strength and excellent transparency, smoothness, etc., and suitable as a film, sheet or inner material of furniture, etc., by compounding a modified polyolefin, a cellulosic material and a specific grafted material at specific ratios. CONSTITUTION:The objective composition can be produced by compounding (A) a modified polyolefin resin added with 0.1-14wt% unsaturated carboxylic acid (derivative), or a mixture of said modified polyolefin and an unmodified polyolefin, (B) a cellulosic material (e.g. wood pulp) and (C) a grafted material produced by grafting a polyoefin resin modified with an unsaturated carboxylic acid (derivative) to a cellulosic material. The amount of the modified polyolefin resin is >=3pts.(wt.), preferably >=4pts. per 100pts. of B+C. If necessary, the composition is compounded with (B) 2-40pts. of a plasticizer (e.g. dimethyl phthalate) based on 100pts. of A+B.