Abstract: A small-sized electric mechanical transducer wherein plates are disposed to surround a bobbin in association with yokes. Magnetic passages are formed among the plates. Each of a pair of magnets drives the bobbin in accordance with the electric signals input into the driving coil. Also, an optical type pickup apparatus positively capable of the signal reading operation in which the lens holder is not out of shape even if the lens holder is driven in the focusing direction and the tracking direction, because the gravity center of the lens holder is conformed to the action point of the resultant force of the forces to be produced by the control signals to be input into the driving coil, and by the magnetic field of the magnetic circuit.

Abstract: A optical type pickup apparatus wherein the center of gravity of the lens holder coincides with the action point of the resultant force of the forces to be produced by the control signals input into the driving coil and by the magnetic field of the magnetic circuit. Thus, this apparatus may be provided which is capable of a signal reading operation wherein the lens holder is not out of shape even if the lens holder is driven in the focusing direction and the tracking direction.