A probe includes a plurality of optical fibers that includes an irradiation fiber and a light-receiving fiber; and an optical member of which a base end face is arranged to abut on leading end faces of the optical fibers, and a leading end face is exposed to an outer side. The leading end face of the optical member is perpendicular to a longitudinal direction of the probe. Light emitted from the irradiation fiber passes through a path inclined with respect to a perpendicular line of the leading end face.