A confocal scanning microscope including: an objective system (second objective lens 23 and objective lens 24) illuminating a sample SA with illumination light; a scanning mechanism 31 scanning the sample SA to obtain an intensity signal; and a scanning optical system 32 provided between the scanning mechanism and the objective system. The scanning optical system composed of, in order from the scanning mechanism side, a first positive lens group G1, a second negative lens group G2, and a third positive lens group G3. The third lens group has two chromatic aberration correction portions each formed by a positive lens and a negative lens or negative lens and positive lens. Glass materials are selected such that one performs chromatization and the other performs achromatization, thereby providing a confocal scanning microscope capable of correcting lateral chromatic aberration generated in the objective system in the specific wavelength region by the scanning optical system.