Abstract: A molding machine having a plunger replacement apparatus is disclosed. Molding operation of the molding machine for a plunger requiring replacement is only discontinued, and the plunger requiring replacement is taken out to a plunger replacing position through a reciprocating mechanism. Moving yokes are locked by locking mechanisms to fixed yokes at the pressing and plunger replacing positions. The position of the plunger is always held constant during the process of replacement at the plunger replacing position and also when the plunger is returned to the pressing position. When the plunger requiring replacement is taken out in a plunger replacing position, molding operation for the molding machine is continued by using the remaining plungers, thereby minimizing possible drop in molding operation productivity and preventing undesirable changes in temperature distribution conditions.