An endoscope apparatus includes: a light source portion that irradiates an excitation light and a reference light alternately an image pickup portion that picks up images of the fluorescence from the living tissue and the reflected light a signal processing portion that generates image signals from picked up signals an addition processing portion that generates, from image signals of fluorescence, addition processed signals of fluorescence in which pixels are added a light quantity control portion that controls the quantity of light so as to maintain a predetermined light quantity ratio between the quantities of the excitation light and the reference light from the addition processed signals of fluorescence and image signals of the reflected light and a superimposition processing portion that superimposes the addition processed signals and the image signals of the reflected light, with the predetermined light quantity ratio being maintained.
