Provided is a method for producing a molded product comprising a step for preparing a polymerizable composition for optical materials and a step for curing the polymerizable composition for optical materials to produce the molded product. The step for preparing the polymerizable composition for optical materials comprises a step for preparing a defined polythiol compound and a step for preparing the polymerizable composition for optical materials from the polythiol compound. The step for preparing the defined polythiol compound comprises reacting 2-mercaptoethanol with a defined epihalohydrin compound at a temperature of 10° C. to 50° C. to obtain a defined polyalcohol compound, reacting the polyalcohol compound with thiourea in the presence of hydrogen chloride to obtain an isothiuronium salt, hydrolyzing the isothiuronium salt to obtain the polythiol compound, adding hydrochloric acid at a defined concentration to a solution of the polythiol compound, and washing the solution to purify the polythiol compound.