Woody synthetic resin compositions

A woody synthetic resin molded article equivalent to natural wood in secondary processing properties such as nailing, sawing and screw clamping, excellent in strength/rigidity, and having no surface roughness to show good appearance can be stably formed by a woody synthetic resin composition containing 5 to 95 parts by weight of (A) a thermoplastic resin, 5 to 95 parts by weight of (C) a vegetable cellulose and, per 100 parts by weight of (A)+(C), 0.1 to 10 parts by weight of (B) an ultrahigh molecular weight polymer having a viscosity average molecular weight of 1,200,000 or more, wherein the thermoplastic resin (A) contains (J) a polyolefin resin composition.