A track of an optical disk is formed by wobbling and divided into zones, a clock ratio of a recording clock to a wobble clock is preset for each zone, a wobble signal is detected from the optical disk, the wobble clock is generated from the wobble signal, a present position is identified by reproducing ADIP indicating a position of the track from the wobble signal and the wobble clock, the recording clock is generated with respect to the wobble clock, a data address present position is identified from the present position, a start end position of the ADIP in a recording target zone, a start end position of the data address in the recording target zone, and the clock ratio, a recording start position is identified based on the data address present position; and the data is recorded from the recording start position of the recording target zone.