A controller in which an actuator has a shape memory alloy (SMA), for controlling a position of a member driven by the actuator. The controller includes the SMA, a spring coil connected to the SMA, an operation device for calculating a voltage to be supplied to the SMA on the basis of information upon a target position and an actual position of the member, a voltage supplying device for supplying the voltage to the shape memory alloy on a basis of a result of operation performed by the operation device, only when the member is moved in a direction in which the SMA returns to a predetermined length that is memorized by itself.