An optical disk recording/reproducing device which records a signal on a disk using a laser beam irradiated from a laser element driven by a pulse signal, wherein an average level detector circuit (70) detects an average level of a monitor signal obtained when a basic pulse signal is applied to the laser element, and an average level of a monitor signal of a reference basic pulse signal is stored as a reference average level in advance in a memory (15). During an actual recording operation, writing in a trial writing region is performed. During the trial writing, a system control circuit (9) compares the presently detected average level to a reference average level stored in the memory (15), and corrects waveform of the basic pulse signal by adjusting a peak level and/or a bottom level of the basic pulse signal to be output such that the detected average level matches the reference average level.