The present application detects a state change of an object in an optical axis direction by a single frame scanning for each round. A confocal microscope apparatus includes a detecting unit separating incident light into a light from a vicinity of a collecting point on the sample and a light from a peripheral of the vicinity and detecting each of the lights, and an image generating unit generating an image of the sample by a light signal from the vicinity and a light signal from the peripheral, in which a distinction between a light signal from the vicinity and a light signal from the peripheral is calculated for each of a plurality of images generated in a number of times of scanning without changing a collecting location in an optical axis direction.