An optical disk apparatus includes a detector for detecting a data string corresponding to a waveform pattern having a predetermined time width, an ideal signal generator for generating a data string of an ideal signal having a predetermined time width, which corresponds to a data string having the predetermined time width, a parameter calculator for comparing the detected data string with the data string of the generated ideal signal, and determining a waveform compensation amount on the basis of the comparison result, a recording waveform generator for generating a recording waveform pulse on the basis of externally supplied recording data and the waveform compensation amount, and a pickup for irradiating a storage area of the optical disk with a laser beam in accordance with the recording waveform pulse to record the recording data.