To obtain the subject molding high in hinge durability, having a structure in which a specific oxyalkylene unit is inserted into a polymer having an oxymethylene unit in a prescribed ratio.

A polyoxymethylene copolymer having a structure in which an oxyalkylene unit is of the formula (R and R0 are each H, an alkyl, an aryl and R bonded to different carbon atoms and R0 bonded to different carbon atoms are each H, an alkyl or an aryl; (n) is an integer of ≥2, the ratio in which n=1 is ≥95mol% and the ratio in which n≥2 is ≤5mol% based on the whole oxyalkylene units, respectively (m) is 2-6) is inserted into a polymer composed of a repeating unit of an oxymethylene unit (CH2O) in the ratio of 0.07-0.5mol of the oxyalkylene unit based on 100mol oxymethylene unit in which the end group of the polymer is mainly an alkoxy group, a hydroalkoxy group and a formate group is molded by injection molding machine to give the objective molding having a hinge part excellent in durability and restoring force.