An optical disk apparatus having an optical head for reading and writing signals on an optical disk and a signal processing unit for performing predetermined signal processing on the signals is disclosed. The apparatus includes a first controller, a second controller, a detector, and an adjuster. The first controller controls the optical head to write a predetermined signal on a predetermined area of the optical disk with various levels of recording power of the optical head. The second controller reproduces the predetermined signal written on the predetermined area of the optical disk. The detector attempts to detect a predetermined signal pattern having a predetermined period from the reproduced signal with different slice levels. The adjuster determines a resolution of the reproduced signal in accordance with a slice level with which the signal pattern can be detected and automatically adjusts the recording power of the optical head based on the determined resolution.