a scanning microscope includes : a light source ; an optical system that irradiates light from the light source onto a sample while two - dimensionally scanning the light , and collects light from the sample ; a photo - detector that receives the light from the sample which has been collected by the optical system , and converts the light thus received into a brightness signal ; an integrating circuit that integrates the brightness signal from the photo - detector for each pixel ; and an image forming circuit that forms an image of the sample based upon the brightness signal of each pixel integrated by the integrating circuit . and the integrating circuit includes a plurality of integrators for integrating the brightness signal from the photo - detector and an adder for adding output signals from the plurality of integrators , and integrates the brightness signal while sequentially switching the plurality of integrators for each of a plurality of periods obtained by dividing a period corresponding to a pixel .