A recording and reproducing apparatus includes a spatial-light-intensity modulating unit, a spatial-light-phase modulating unit, an optical system that transmits light and leads the light to a hologram recording medium, a converting unit that converts an input data sequence; an amplitude and phase controlling unit that controls, during recording, the spatial-light-intensity modulating unit and the spatial-light-phase modulating unit to generate a signal light and a reference light, and controls, during reproduction, light intensity of each of pixels in a reference light area and a signal light area and controls a phase of each of the pixels, an image-signal acquiring unit that receives the reproduced image and the DC light and obtains two kinds of image signals, a difference calculating unit that calculates a difference between the two kinds of image signals, and a decoding unit that decodes data formed by a combination of the two kinds of values.