An optical disk device for writing information on an optical disk having an APC part for monitored driving of a laser diode is provided which performs first and second OPCs. An unused partition of a test area and reference power value are read out from the optical disk. APC is turned off if the recording speed exceeds 1. A first optimum writing power value is obtained by writing on the unused partition by driving the laser diode at a plurality of first test laser power values centered on the reference power value and reading out the information. APC is turned on if the recording speed exceeds 1. A second optimum writing power value is obtained by writing on a subsequent unused partition by driving the laser diode at a plurality of second test laser power values centered on the first optimum writing power value and reading out the information.