Confocal scanning microscope

A confocal scanning microscope that irradiates a specimen with a stimulating light beam that causes optical chemical change to the specimen, focuses an exciting light beam to an exciting light beam focal point so as to irradiate the specimen with the exciting light beam, and scans the exciting light beam at least in a plane perpendicular to a depth direction, thereby allowing observation of fluorescence which also indicates the influence of the stimulating light beam, comprising:

• a stimulating light beam scanning unit that scans at least a predetermined plane perpendicular to the depth direction of the stimulating light beam focal position;
• a stimulating light beam scanning control unit that controls the scanning area of the stimulating light beam to a desired area;
• an exciting light beam scanning control unit that controls the scanning area of the exciting light beam to a desired area;
• an exciting light beam focal position changing unit, provided in an excitation fluorescence optical path, which is a portion of an optical path where the exciting light beam and the fluorescence pass and located outside a common optical path where the exciting light beam, the fluorescence, and the stimulating light beam pass, that changes at least the exciting light beam focal position in the depth direction;
• and
• an exciting light beam control unit that controls the exciting light beam focal position variably to a desired position.