An optical disk recording apparatus and method utilize a recording beam source, a spatial light modulator that modulates a recording radiation beam into an information beam carrying information and a reference beam, a focusing unit that focuses the information beam and the reference beam on an information recording layer, an image sensing device that detects the intensity distribution of the information beam, and a control unit. The control unit controls the spatial light modulator on the basis of the intensity distribution detected by the image sensing device. A recording/reproducing apparatus can check the amount of information capable of being recorded onto an optical disk, and an optical disk therefor.