A recording/playback apparatus includes a light-generating and intensity-modulating section for generating signal light and reference light to be shined on a hologram recording medium and a phase modulating section for performing phase modulation on the signal light and the reference light on the basis of a pixel unit by using the first to nth phase modulation levels. For the phase modulation on the reference light, all pixels corresponding to the reference light are divided and set using random phase units, each having a predetermined pixel array pattern having at least two pixels, the number of pixels corresponding to each of the first to nth phase modulation levels in each random phase unit is common to the random phase units, and the array pattern of the pixels corresponding to the first to nth phase modulation levels is random for each random phase unit.