To provide a method for continuously producing a polyethylene terephthalate, further rapidly progressing an ester interchange reaction and also capable of inhibiting the formation of residual foreign materials caused by the residual ester interchange catalyst and thermal decomposition in producing the polyethylene terephthalate by using dimethyl terephthalate and ethylene glycol as main starting materials and a titanium compound which is not a heavy metal, as the ester interchange catalyst.

This method for continuously producing the polyethylene terephthalate by passing through at least 2 stages of the ester-interchanging reaction and a polycondensation reaction in the presence of the titanium catalyst is provided by having the dimethyl terephthalate, ethylene glycol and an ethylene terephthalate oligomer having exchange reaction rate of 70% at the starting of the ester interchange reaction, having 0 and 50 ppm used amount of the titanium catalyst as the titanium metal atom based on the weight of the obtained polyethylene terephthalate, adding 20 mmol% alkali metal compound based on the dimethyl terephthalate in an optional stage until the completion of the ester-interchanging reaction and further performing the polycondensation reaction of the ethylene terephthalate oligomer obtained in the ester-interchanging reaction.