PURPOSE: To prevent breakage of a glass by the displacement of a locating pin even when the end surface of the glass is strongly pushed onto the locating pin by providing a slidable locating pin which serves as a standard for location of the glass on the mold of one side pinch holding the glass.

CONSTITUTION: A horizontal locating-pin 19 controlling the position in horizontal direction of a glass 1, is provided on a cavity block 16. The locating pin 19 is slidable, between the solid line-position projecting into the space past R of a product and the position retreating from the space part R of the product, i.e. the retreating position to be controlled by a stopper 21, in the direction perpendicular to the glass end surface 1a, and the pin may keep the solid line- position by introducing air into a space 23 from an air feeding path 24. In order to position the glass, as an insert, based on the locating pin of slide-type retracted from the space part of the product by material injecting pressure, the locating pin also may follow the glass displacement generated by correction of the curvature of the glass, whereby the breakage of the glass does not occur.