An injection molding machine that contributes to improving the quality of a workpiece is provided. An injection molding machine configured to causes torpedo pistons to be slid in one way to thereby plasticize a resin material supplied to a first space of a cylinder, and causes a molten resin to flow into a second space of the cylinder and causes the torpedo pistons to be slid in the other way to thereby inject the molten resin. The injection molding machine includes pressurizing pistons inserted into the torpedo pistons so that the pressurizing pistons can be slid in such a way that an amount of protrusion of the cylinder into the second space of the cylinder with respect to the torpedo pistons is changed, and energizing means for energizing the pressurizing pistons toward the second space of the cylinder.