A microscope apparatus includes: an objective lens; a CCD that constructs an image of a sample S; an illumination intensity change unit for adjusting an intensity of excitation light; a sensitivity adjustment unit for adjusting a detection sensitivity by the CCD; a galvanometer mirror for changing a light focusing position of excitation light at a pupil position of the objective lens; a storage unit that stores, for each observation method, a predetermined intensity, a predetermined detection sensitivity, and the light focusing position; and a control unit that switches the observation method, reads out the intensity, the detection sensitivity, and the light focusing position according to the observation method based on a synchronization signal synchronized with a frame signal for constructing an image, and controls the illumination intensity change unit, the sensitivity adjustment unit, and the galvanometer mirror.