A light transmitting probe comprising: a housing for fixing the probe to a mounting portion of a holder to be mounted on a subject a light emitter for emitting light, the light emitter being placed in an end portion of the housing and a transmission channel, one end of which is connected to the light emitter, and the other end of each is connected to a controller the light transmitting probe irradiating the subject with light when fixed to the holder, and being characterized in that the end portion of the housing has a number of rod-shaped protrusions, the light emitter is a number of light emitting elements, the light emitting elements are respectively placed in an end portion of each protrusion, the transmission channel is a number of transmission channels, and the transmission channels are respectively placed inside each protrusion.
