an injection apparatus of an injection molding machine includes a heating cylinder and a screw disposed in the heating cylinder , and the screw is axially moved and rotated in the heating cylinder for plasticizing the molten material by mechanisms or devices assembled in the injection apparatus , which is driven by electric drive means through driving power transmission means . the electric drive means comprises two servomotors and the power transmission means comprises two power transmission mechanisms operatively connected to the servomotors respectively so that one of the two servomotors drives a mechanism for axially moving the screw through one of the two power transmission mechanisms and the other of the two servomotors drives a mechanism for rotating the screw through the other of the two power transmission mechanisms , parallelly or concurrently .