A micro actuator for moving a head device in a track direction of a recording medium by a magnetic force generated between the magnetic cores. In normal use, the micro actuator is mounted on an actuator arm which pivots in a track direction across a track of the recording medium. The slider moves above the recording medium and has an accommodating portion facing the recording medium. A first magnetic core is arranged to move in the accommodating portion, for supporting the head device. A second magnetic core, separated a predetermined distance from and facing the first magnetic core, is installed in the accommodating portion such that the center of the first magnetic core in a magnetic direction, which is perpendicular to the track direction and horizontal with respect to the surface of the recording medium, is offset from the center of the first magnetic core. A first magnetic coil is wound around the first magnetic core so that the axis of the first magnetic coil runs in the vertical direction and a magnetic force in a direction perpendicular to a surface of the recording medium is generated when current is applied. Leaf springs elastically connects the first magnetic core and the inner side of the accommodating portion in the track direction. When current is applied to the first magnetic coil, the first magnetic core is moved in the track direction by a magnetic force generated between the magnetic cores.