This endoscope apparatus comprises an insertion section to be inserted into a space to be inspected, a light emitting device for illuminating inside of the space, a fluorescent member provided at a tip-end of the insertion section and emitting fluorescent light with light from the light emitting device as excitation light, a light guide transmitting the light from the light emitting device to the fluorescent member, a light branching member for branching a part of the fluorescent light returned from the fluorescent member, and an optical sensor for detecting light from the light branching member, and when the illumination light becomes dark due to a failure or removal of the tip-end section of the endoscope, an image with low luminance is not displayed, glare at replacement of the tip-end section can be reduced to improve workability and the diameter of the insertion section can be thinned.