A method for controlling a screw position of a screw in an injection molding machine uses a high-speed injection and high-speed depressurization method to perform the entire injecting process by controlling speed of the screw. The screw is moved forward to a predetermined first position from an injection start position, and when the screw reaches the predetermined first position, the screw is moved backward to a predetermined second position. The speeds of the forward and backward movement of the screw are controlled in accordance with a screw-position/speed characteristic pattern which is measured in advance, and which is derived from the equation Vnull(2nullKnullS)null where V is screw speed, K is screw acceleration, and S is screw position.