Abstract: The present disclosure relates to a molding apparatus for fixing a magnet in a rotor core of a permanent magnet synchronous motor. The present disclosure provides a molding process for a rotor of a motor which can reduce manufacturing costs through alleviation of a tolerance of an introduced product and reduction of an error rate of a finished injection-molding product, by applying a lift core which may variably move in a mold during an insert injection molding process for molding a rotor and accordingly a new type of rotor molding method for a permanent magnet synchronous motor which prevents generation of a flash in an injection molding process even when the size and tolerance of the introduced product deteriorate as compared with a mold.