To prevent a heating cylinder from falling down during nozzle touching and control an injection screw so as to achieve its smooth movement and correct positioning during injecting/batching by ensuring smooth ascent/descent of an injection device along a guide rail.

This electric power vertical injection molding machine 1 is equipped with an injection device 7 of the following constitution: a front plate 11 is supported by guide rails 5 and 5 on a moving platen through direct-acting guides 6, the device 7 is lifted by an injection device lifting means with a ball screw mechanism B2 to the moving platen along the guide rails 5 and 5, and an injection nozzle of the heating cylinder 8 is made to come into contact with and move apart from a movable half of a mold. In addition, the heating cylinder 8, a motor for screw rotation, a motor for injection 17 and each axis C1, C2 and C of the ball screw mechanism B2 pass through the center Co of the guide rails 5 and 5 and are arranged in one straight line L orthogonal with a straight line Lo connecting each guide rail 5 and 5 together as viewed on a planar angle. Further, the axes C1 and C2 of the heating cylinder 8 and the motor for injection 17 are arranged opposite to each other with the axis C of the ball screw mechanism B2 located in between.