PURPOSE: To adjust the moving speed of a plunger and to cast a casting having no cavity by providing a specific port to a molten metal injection cylinder of a die casting machine, and communicating the port with an oil feed pipe having no restricting resistance only in the initial period of the operation of a plunger.

CONSTITUTION: The molten Al in a casting sleeve 5 is pressurized and cast in dies consisting of a stationary die 1 and a movable die 2 by the tip 7 of a plunger 4 which is actuated by a cylinder 3. A spool 23 having a compression spring 24 is disposed in the cylinder 22, and a port 34 is provided at the intermediate of the cylinder 22 and is communicated with an oil feed pipe 35 to an oil tank 29. The pressure oil in the cylinder 22 escapes at a high speed in the oil feed passage 35 having no restricting resistance only in the initial period of operation of the spool 23 and therefore a restricting valve 32 communicating with another port 26 of the cylinder 22 is adjusted to delay the high speed transfer time of the plunger and in succession, the molten metal 6 is pressurized and cast in the dies at a high speed, whereby the die cast product having no cavity is obtd.