A magnetic head driving apparatus makes it possible to effect a correct positioning operation at the assembly of the magnetic head, and also, to effect the correct measurement of the gap positions of the magnetic head. Also, the magnetic head is immune to the influence of the leakage flux of the magnetic circuit. Coil bobbins are mounted in a first gimbal spring and a second gimbal spring and the head has a projection in its lower end portion. The projection portion is extended through the hole of the first yoke. The head base is secured with a fixing member in the projection portion. A head base extending portion extending in a radial direction is formed in one portion of the external periphery of the head base with a magnetic head being mounted on its tip end. A sensor object showing the gap position of the magnetic head is formed in one portion of the head base extending portion.