An endoscope system includes: a light transmitting section for transmitting illuminating light and emit the light from a light exit surface a light receiving section for receiving return light of the light emitted from the light exit surface a light guiding section for allowing the light to be incident on the light receiving section by totally reflecting return light from a subject or the emitted light at least one or more times a driving section for allowing an end portion having the light exit surface of the light transmitting section to be swung a light detecting section for detecting the light received through the light guiding section, as a signal and a control section for, if the pattern of fluctuations in the signal level by the light detected by the light detected section does not correspond to the predetermined pattern of fluctuations, performing control for lowering a quantity of the illuminating light.
