The endoscope apparatus of the present invention comprises an insertion section inserted into a space to be inspected, a light emitting device for emitting excitation light, a fluorescent member for emitting illumination light obtained by mixing the excitation light and fluorescent light excited by the excitation light into the space from the tip end of the insertion section, an optical sensor for detecting return light, a part of the illumination light, a light guide for light detection provided with one end facing the fluorescent member and the other end facing the optical sensor for transmitting the return light emitted from the fluorescent member to the optical sensor, a wavelength limiting member provided between the other end of the light guide and the optical sensor for limiting the wavelength of the return light, and a light detection portion for detecting intensity of the return light detected at the optical sensor.