A living body observation system includes: an illuminating light generation section configured to generate first light and second light; an image pickup section; a computation section configured to calculate a difference degree indicating a degree of difference between a luminance value of a first image obtained by picking up an image of return light of the first light and a luminance value of a second image obtained by picking up an image of return light of the second light in a same pixel; an enhancement processing section configured to enhance a contrast of the pixel in which the difference degree exceeds a threshold relative to a pixel in which the difference degree does not exceed the threshold; and an observation image creation section configured to create an observation image by using the first image after the process by the enhancement processing section and the second image.