In the hologram recording and hologram-record reproduction using a
one-dimensional optical modulator, the one-dimensional optical modulator
where a plurality of light-modulating pixels are arranged modulates a
laser beam to record a digital-data signal on a hologram recording
medium, and part of the light-modulating pixels record sync signals in
two or more positions on the hologram recording medium with retaining a
predetermined interval, thereby improving hindrance to reproduction or
readout of information recorded on the hologram recording medium, a
decrease in S/N, and so on due to deformation or the like of the hologram
recording medium.