A probe 3 according to the invention includes a plurality of optical fibers having an irradiation fiber 5 and light-receiving fibers 7 and 8 which are arranged such that at least leading end portions are in parallel with each other, and includes a rod 34 of which a base end face is arranged to abut on leading end faces of the plurality of optical fibers, and a leading end face is exposed outside. The leading end face 34a of the rod 34 is perpendicular to a longitudinal direction of the probe 3 and intersects with a longitudinal direction of the leading end portions of the plurality of optical fibers at an acute angle.
