To provide an injection molding machine with a hydraulic actuator that can more efficiently move a driven part up and down.

The injection molding machine 200 with hydraulic actuators 100BL, 100BR, which move an injection device 20 up and down, includes: single rod hydraulic cylinders 1BL, 1BR having head side oil chambers 1BLb, 1BRb and rod side oil chambers 1BLc, 1BRc defined by pistons 1BLa, 1BRa and receiving a self weight pressure of the injection device 20 through use of oil in the head side oil chambers 1BLb, 1BRb; a dual directional hydraulic pump, in which one port is communicated with the rod side oil chambers 1BLc, 1BRc, the other port is communicated with the head side oil chambers 1BLb, 1BRb; and the electric motor for driving the dual directional hydraulic pump, wherein the electric motor drives the dual directional hydraulic pump against pressure of the oil in the head side oil chambers 1BLb, 1BRb which receive the self weight pressure of the injection device 20.