A device for calculating a position of an actuator, the actuator including a movement mechanism configured to move in one direction in proportion to a control signal generated for each minimum movement amount ΔM and a movement amount detection sensor configured to detect a movement amount of the movement mechanism in a minimum resolution ΔS, where A=ΔS/ΔM≧2, and the device includes a position calculation unit configured to calculating a position SA of the movement mechanism at a target position from the control signal at a time point T1, at which the sensor signal becomes (S0+m×ΔS) or (S0−m×ΔS), where m is a natural number of 1 or more, the control signal at the target position of the movement mechanism is denoted by M0, and the sensor signal is denoted by S0.