PROBLEM TO BE SOLVED: To reduce the diameter of a tip hard part of a probe, and to shorten the axial length of the tip hard part of the probe.SOLUTION: This probe includes: a direct-viewing imaging device 11 imaging a direct view direction that is a tip direction of the probe and a side-viewing imaging device 21 imaging a side view direction that is a side direction of the probe. In the probe, an irradiation/light reception direction of a measurement optical system irradiating exciting light and measuring radiation light of fluorescence or the like is the side direction of the probe, and the tip hard part 10 is connected to a second hard part 20 behind it through a soft part 30 in a state that the axial direction is relatively variable to the second hard part 20, the direct-viewing imaging device is mounted in the tip hard part, and a measurement part 40 irradiating irradiation light of the radiation light measurement optical system and receiving the radiation light is mounted in the second hard part.
