To provide an industrially improved method producing an alkali metal salt of glycine useful as a raw material for a food additive of processed food, a medicine or an agrochemical, by hydrolysis of glycinonitrile with an alkali metal hydroxide.

In this method producing the alkali metal salt of glycine by reacting glycinonitrile with the alkali metal hydroxide in the presence of water as solvent, the reaction is carried out in a flow reactor with a stirring tank pressurized under the partial pressure of ammonia ≥0.2 MPa and the reaction of the reaction mixture is completed in a liquid seal type tubular flow reactor.