A process for efficiently producing optically active succinimide derivatives as key intermediates of (3R)-2′-(4-bromo-2-fluorobenzyl)spiro{pyrrolidine-3,4′(1′H)-pyrrolo[1,2-a]pyrazine}-1′,2,3′,5(2′H)-tetraone, which comprises the following reaction steps, and the step 2 is performed by using a non-animal-derived enzyme.