<p>A storage section (50) prestores the difference between an initial start resistance predetermined as the resistance of a shape memory alloy (123) at the time when a lens unit (11) starts movement, and an initial wait resistance predetermined as the resistance of the shape memory alloy (123) at the time when the lens unit (11) is located at a waiting position. A command section (60) adds the difference stored in the storage section (50) to an actual start resistance which is the resistance at the time when the start of movement of the lens unit (11) is detected at a detecting section (40), and sets a target value required for attaining the resulting resistance as the actual target value of the waiting position.</p>
