A confocal scanning microscope comprising: an objective optical system (23, 24) that converges illumination light on a sample and forms a first image plane locating at a conjugate position with the sample; a scanning mechanism that scans a surface of the sample so as to obtain a light intensity signal from the sample; and a scanning optical system that is provided between the scanning mechanism and the first image plane formed by the objective optical system (23, 24), wherein the scanning optical system generates lateral chromatic aberration in an ultraviolet wavelength region in order to correct lateral chromatic aberration generated at the ultraviolet wavelength region in the objective optical system (23, 24); the scanning optical system being composed of, in order from the scanning mechanism side, a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power, the first lens group being composed of a positive lens; the second lens group being composed of a positive lens and a negative lens, the third lens group having two chromatic aberration correction portions each formed by a positive lens and a negative lens or a negative lens and a positive lens adjoining each other, characterised in that when Vh is defined by the following expression: Vh = 1000 × nh - nd / nd - 1 where nd denotes a refractive index at d-line, and nh denotes a refractive index at h-line of an optical material constituting a lens, the following conditional expressions is satisfied: V31 > V32 and V33 < V34 or V31 < V32 and V33 > V34 where V31 denotes Vh value of the positive lens constituting a chromatic aberration correction portion being disposed to the scanning mechanism side among two chromatic aberration correction portions in the third lens group, V32 denotes Vh value of the negative lens constituting the last mentioned chromatic aberration correction portion, V33 denotes Vh value of the positive lens constituting a chromatic aberration correction portion being disposed to the objective optical system side, and V34 denotes Vh value of then negative lens constituting the last mentioned chromatic aberration correction portion. an objective optical system (23, 24) that converges illumination light on a sample and forms a first image plane locating at a conjugate position with the sample; a scanning mechanism that scans a surface of the sample so as to obtain a light intensity signal from the sample; and a scanning optical system that is provided between the scanning mechanism and the first image plane formed by the objective optical system (23, 24), wherein the scanning optical system generates lateral chromatic aberration in an ultraviolet wavelength region in order to correct lateral chromatic aberration generated at the ultraviolet wavelength region in the objective optical system (23, 24); the scanning optical system being composed of, in order from the scanning mechanism side, a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power, the first lens group being composed of a positive lens; the second lens group being composed of a positive lens and a negative lens, the third lens group having two chromatic aberration correction portions each formed by a positive lens and a negative lens or a negative lens and a positive lens adjoining each other, characterised in that when Vh is defined by the following expression: Vh = 1000 × nh - nd / nd - 1 where nd denotes a refractive index at d-line, and nh denotes a refractive index at h-line of an optical material constituting a lens, the following conditional expressions is satisfied: V31 > V32 and V33 < V34 or V31 < V32 and V33 > V34 V31 > V32 and V33 < V34 or V31 < V32 and V33 > V34