Method for producing ß-lactam compound

A method for producing a β-lactam compound, the method comprising:

• introducing, into different flow channels, each of
• a reaction solution (i) obtained by dissolving a metal salt (y) represented by Formula (2) generated by introducing, in a solution obtained by dissolving a metal salt (x) represented by Formula (1), a protective group into an amino group of the metal salt (x),
• a solution (ii) obtained by dissolving an acid halide, and
• a solution (iii) obtained by dissolving a β-lactam compound (a) having an amino group, and causing each solution to flow in each flow channel;
• merging the reaction solution (i) and the solution (ii) to cause the metal salt (y) and the acid halide to react with each other in a merged solution (M1) while the merged solution (M1) flows downstream to generate a mixed acid anhydride;
• and
• merging the merged solution (M1) and the solution (iii) to cause the mixed acid anhydride and the β-lactam compound (a) having an amino group to react with each other in a merged solution (M2) while the merged solution (M2) flows downstream to generate a β-lactam compound (b) having an amide bond,
• in the formulae, R represents a cyclic hydrocarbon group, M represents an alkali metal, and X represents a protective group.