According to one embodiment of the present invention, there is provided a photon generating apparatus including: a light source configured to emit light; an optical medium configured to generate a pair of photons from the light; a detector configured to detect one photon from the pair of photons and output a detection time of the photon; a buffer including an optical line and an optical switch disposed on an optical path of the photon, which is one photon except for the photon detected by the detector, of the pair of photons; and a processor configured to output a driving signal which controls the optical switch so that a delay occurs at the optical path using the detection time of the photon detected by the detector.