The production method for an alpha,alpha-difluoroacetaldehyde hemiacetal ("DFAL-ROH") according to the present invention comprises a step in which a difluoroacid ester is reacted with hydrogen (H2) ina reactor in the presence of a base and a ruthenium catalyst to produce a mixture containing a DFAL-ROH; a step in which the mixture is neutralized, thereafter the oxygen concentration inside the reactor is regulated to 5,000 ppm or less under such conditions that the mixture is shielded from light, and then distillation is conducted to obtain a mixture comprising the DFAL-ROH and a dimer and having a pH of 3.5-10.0; and a step in which an alcohol is added to the mixture after the oxygen concentration inside the reactor is regulated under light-shielding conditions, thereby obtaining a DFAL-ROH-containing mixture from which at least some of the dimer contained in said mixture has been removed or substantially all the dimer contained in said mixture has been removed. By the method, a DFAL-ROH reduced in by-product content is efficiently obtained.