An actuator of an optical disk system and an apparatus producing a signal for driving the actuator, the actuator including a light source, with which information is recorded on or reproduced from an optical disk surface. In the actuator, an inner focusing coil and an outer focusing coil are installed near an inner boundary and an outer boundary, respectively, of the optical disk surface. A first signal wire is connected to a first port of the inner focusing coil and transmits an inner coil signal. A second signal wire is connected to a first port of the outer focusing coil and transmits an outer coil signal. A common signal wire is connected to a second port of the inner focusing coil and a second port of the outer focusing coil and transmits a common reference signal. Thus, a simple, inexpensive 8-wire actuator can be obtained.