An offset adjustment signal is recorded in a test recording area provided
on the inner side of a disc while modifying the level of a driving signal
for offset detection that is supplied to a tilt adjustment coil.
Thereafter, an operation to play back the offset adjustment signal is
performed, and a .beta. value is detected from an RF signal that is
played back. When a signal is recorded for which the detected .beta.
value reaches a maximum, the level of the driving signal supplied to the
tilt adjustment coil is set as an offset value. Tilt control is then
performed by adding the offset value to a tilt signal for performing tilt
control.