PURPOSE: To prevent the horizontal slip generated at the time of ejecting a molded product and improve the releasing by forming an ejecting section of sectional area smaller than the sectional area of an ejection pin on the end of the ejection pin of round sectional shape for ejecting the molded product from a mold.

CONSTITUTION: A molded product 7 is molded by injecting resin into a cavity formed by a fixed side mold 2 and a movable side mold 3 by mold clamping an injection molding die 1. At that time, the diameter (d) of an ejection section 8 formed at the end of an ejection pin 4 is smaller than the diameter D of the ejection pin 4, and resin is filled in a space between two diameters. The movable side mold 3 is separated after molding to eject the ejection pin 4, and an inclined core 6 is moved to separate an undercut section 9 and carry out releasing. At that time, although a horizontal slip force is applied to the molded product 7 by the release resistance of the undercut section 9, the horizontal slip force is controlled by the resin filled in the ejection pin 4 to generate no defective release of the molded product 7.