A biological observation system includes: a light source section generating illumination light including at least first illumination light with a center wavelength from a red region to a near infrared region of a visible region a light detection section receiving return light emitted from a region to be observed to which the illumination light is applied and outputting an output signal a signal processing section generating a frequency spectrum signal indicating a frequency spectrum of the return light emitted from the region to be observed according to application of the first illumination light an image generation section generating an intensity image based on the output signal and generate a frequency spectrum image based on the frequency spectrum signal and a display control section generating and displaying an observation image of the region to be observed by using the intensity image and the frequency spectrum image.
