To provide a method for industrially producing an α-amino-γ-butyrolactone or a salt thereof with a short reaction time, with high yield, and with excellent operability, especially to provide the method for industrially producing the α-amino-γ-butyrolactone or the salt thereof having high optical purity, wherein an asymmetric carbon is less likely to be isomerized in the method.

A method for producing the α-amino-γ-butyrolactone or the salt thereof comprises a step where methionine and a chloroacetic or bromoacetic acid are caused to react with each other in a solvent. The solvent contains 60 wt.% or more of water relative to the total weight of the solvent.