A probe (4) is provided with at least a light projecting optical fiber (9) and a light receiving optical fiber (10) and is configured so that excitation light guided by the light projecting optical fiber is applied to the portion of a living organism which is to be observed and then light emitted, due to the excitation light, from the portion to be observed is received by the light receiving optical fiber. The probe (4) is also provided with an illumination means used for the capture of an image by the image capturing means of an endoscope body. The illumination means is, for example, a light emitting diode which is provided to the front end of the probe, a light guiding optical fiber (11) which guides illumination light from an illumination light source (5c) to the front end of the probe, or a light emitting substance piece which is disposed at the front end of the probe and emits white fluorescent light by excitation.