To provide a polyacetal resin material improved particularly in sliding characteristic, while keeping inherent properties of polyacetal resin, such as excellent appearance, rigidity, heat stability, etc.

This polyacetal copolymer is obtained by copolymerizing 100 pts.wt. trioxane (A), 0.01-40 pts.wt. polysiloxane compound (B) having at least a cyclohexene oxide group, and 0-20 pts.wt. cyclic ether compound (C) capable of copolymerizing with trioxane.