Provided is a method for producing a compound expressed by the following formula (3): [where R1 represents a hydrogen atom or C1-4 alkyl group, and R2 represents C1-4 alkyl group, C1-4 alkoxy group, aryl group, aryloxy group or benzyloxy group], the method comprising a reaction of dehydro-condensing a compound expressed by the following formula (1) and a compound expressed by the following formula (2): while being converted to a desired geometric isomer in the presence or absence of an acid catalyst, under a condition that an organic solvent to be used for the reaction is a mixed solvent of acetic acid and a solvent selected from the group consisting of toluene, xylene and chlorobenzene.