There are provided a photodetection device, a photodetection method, a microscope and an endoscope, which are capable of heterodyne-detecting desired light to be detected with high sensitivity and high S/N ratio, among which the photodetection device includes: a local light generation unit (10) generating local light having a plurality of optical frequency components in an optical frequency band of light to be detected within a given period of time; a light combining unit (20) combining the local light generated from the local light generation unit (10) and the light to be detected; and a photoelectric conversion unit (30) photoelectrically-converting light output from the light combining unit (20) and generating a beat signal of the local light and the light to be detected, such that the light to be detected is heterodyne-detected based on an output of the photoelectric conversion unit (30).