Abstract: Provided is a spatial light modulator SLM and a photodetector element CMOS sensor are placed on the same chip, and the alignment thereof and a relay lens system are eliminated, whereby an optical system is reduced in cost and made compact. Specifically, provided is an optical information recording and reproducing apparatus for recording information by allowing information light and reference light to interfere with each other and reproducing the information using the reference light including: a light source; a spatial light modulator for generating at least an information light with respect to a light beam from the light source; an objective lens for irradiating a recording medium with the light beam from the spatial light modulator; and a photodetector element for receiving a reproduction light from the recording medium, in which the spatial light modulator and the photodetector element are formed on the same semiconductor substrate.