PURPOSE: To conduct injection molding for a molding of high quality without requiring the correction of molding conditions even when there is a dimensional difference from an aspect of production between movable molds by setting molding conditions at every two movable molds having the same structure.

CONSTITUTION: The molding conditions at every combinations of a fixed mold 1 with a plurality of movable molds 2, 3 having the same structure are set to the inherent molding conditions at every movable molds 2, 3. Identification displays 2a, 3a are provided to the movable molds 2, 3. The movable mold 2 is specified before the mold clamping with the fixed mold 1 by reading the identification display 2a to alter molding conditions to the inherent molding conditions of the movable mold. Thereafter, the movable mold 2 and the fixed mold 1 are clamped to perform injection molding.