To provide a method for manufacturing a lock pin that is easily manufactured in a simple composition.

The lock pin is used in a push-and-push type ejection mechanism for a card connector, and the method for manufacturing the reverse U shaped lock pin having first and second leg sections and a connecting section for connecting the first and second leg sections includes at least (a) a step for cutting out blanks having shapes corresponding to the lock pin of the reverse U shape from a metal plate and (b) a step for applying rounding processing to a section corresponding to the first leg section and the second leg section that are cut out into rectangular cross sections for the lock pin of the reverse U shape and forming so that the cross sections of the first leg section and the second leg section form circles.