Injection device for die casting machine

A hybrid injection device for a die casting machine, in which a large electric power loss is prevented from occurring by avoiding a large current during pressurizing and holding operation and in which the size of a motor is reduced. The injection device has an injection cylinder (16) for receiving an injection piston (15) for injecting a molten metal into a mold and an electric booster (8) operating with a hydraulic cylinder. A head chamber (8H) of an electric booster is fluidically communicated with the head chamber (16H) of the injection cylinder. The head chamber (8H) linearly moves a booster piston rod (5) received in the electric booster (8) to push and move the injection piston, performing injection molding. Because a stop valve (25) is installed in a pipe interconnecting the head chamber (16H) of the injection cylinder and the rod chamber (8R) of the booster (8), the injection device can produce pressure by the head area of the electric booster during the boosting and produce pressure by the rod area t