Production method for episulfide compound

A production method for an episulfide compound, which comprises:

• (A) producing an episulfide compound having two or more units of the structure represented by the following formula (2) from an epoxy compound having two or more units of the structure represented by the following formula (1);
• and
• (B) adding a mixed solvent of a protic polar solvent and an aprotic polar solvent to a reaction solution obtained after (A) the producing of the episulfide compound
• wherein R1 represents a hydrocarbon group containing 0 to 10 carbon atoms, R2, R3 and R4 each independently represent a hydrocarbon group containing 1 to 10 carbon atoms or a hydrogen atom, Y represents O, S, Se or Te, and n represents 0 or 1,
• wherein R1 represents a hydrocarbon group containing 0 to 10 carbon atoms, R2, R3 and R4 each independently represent a hydrocarbon group containing 1 to 10 carbon atoms or a hydrogen atom, Y represents O, S, Se or Te, and n represents 0 or 1.