PURPOSE: To start a disk at an optional radius position, by accelerating again a CLV disk until it reaches a state in which a spindle servo control can be locked after detecting the end of the pull-in action of a focus servo control.

CONSTITUTION: A pull-in action is secured for a focus servomotor when a focus servo control signal (s) is set at a high level. Thus the pull-in detection signal (u) is set at a high level. As a result, the switch signal (m) is set at a high level to turn on the tracking servo control. At the same time, an accelerating action is carried out with the switch signal (z) kept at a high level. When the reproduced extracting signal (x) is set at a high level, the signal (z) is set at a low level. At the same time, the switch signal (y) is set at a high level, and a spindle servo action is performed to end the start of a disk.