A method for producing polybutylene terephthalate comprising continuously esterifying a dicarboxylic acid component consisting essentially of terephthalic acid with a diol component consisting essentially of 1,4-butanediol followed by polycondensing the resulting oligomer, wherein the esterification is effected in a molar ratio, P, of the diol component to the dicarboxylic acid component to fall between 1.1 and 1.6, in the presence of a combination of an organic titanium compound and an organic tin compound that satisfies the following requirement:amount of organic titanium compound (mol %).ltoreq.0.08.times.P-0.07where P=molar ratio of diol component to dicarboxylic acid component, and is followed by the polycondensation.