PURPOSE: To prevent an objective and a recording medium from being broken accidentally by providing a lens barrel returning means which returns a lens barrel to the upper-limit position of a movement range when the lens barrel is not driven.

CONSTITUTION: While no control current flows through a feeding coil 6, the lens barrel 4 is at the upper-limit position where it exceeds the maximum amount of surface deflection of the recording medium. When recording or reproducing operation is started, a light beam 2 from a light source is focused on the recording medium 1 through objectives 3a, 3b, 3c, and 3d. At this time, the magnetic force of a magnet 9 fixed to a main body 8 is weak, so when a control current flows through the feeding coil 6, the lens barrel 4 is driven to a specific position in an optical-axis direction to move the objectives 3aW3d to focusing positions. When no control current flows through the feeding coil 6 owing to a paper failure or fault, the magnet 9 and a ring 7 attract each other to return the lens barrel 4 to the upper-limit position of the movement range.