The problem to be solved is to provide a process for producing a polyoxymethylene copolymer in a molding machine with a reduced generation of formaldehyde gas. In a process for continuously producing a polyoxymethylene copolymer comprising a step of melt-kneading a crude polyoxymethylene copolymer at a temperature not lower than the melting point thereof, devolatilizing under reduced pressure the formaldehyde gas generated as a decomposition product, subsequently mixing a formaldehyde scavenger containing a hydrazide compound (A) while keeping the copolymer in a molten state and immediately pelletizing the mixture, a dispersed solution obtained by slurry-dispersing said (A) in a diluent (B) having a melting point lower than temperature (Ta) which is the lower of the melting point and the decomposition temperature of (A), within a temperature range not lower than the melting point of (B) and lower than (Ta) is used as the formaldehyde scavenger.