PURPOSE: To cancel inertial force by coupling a canceling spring symmetrical with a track spring holding an objective lens with a column, fitting a balancer atop and bringing two auxiliary arm other-end sides with both ends of the track spring and clamping the spring.

CONSTITUTION: A movable member 3 holding the objective 2 is coupled with the base column 12 though one track spring 10 provided orthogonally with a recording medium. The movable member 3 is moved by the deflection of the track spring 10 to drive the objective 2 in a track direction. Then the canceling spring 18 is coupled with the base column 12 symmetrically with the track spring 10 and the balancer 14 is fitted atop of it. Then other-end sides of the auxiliary arms 13a and 13b whose one-end sides are coupled with the balancer 14 are brought into contact with both the ends of the track spring 10 to clamp the track spring 10.