A measurement probe is detachably connected to a living body optical measurement apparatus which optically measures a body tissue. The measurement probe includes an illumination fiber which radiates illumination light on the body tissue, a light reception fiber which receives return light of the illumination light reflected and/or scattered by the body tissue, an optical element which abuts on the illumination fiber and the light reception fiber, and fixes a distance between the illumination fiber and the light reception fiber, and the body tissue, an optical member which is provided at a tip of the measurement probe, and which includes a hollow portion which forms a hollow space, and a transmittance change unit which is provided in the hollow portion, and which changes a transmittance of light incident on an interior of the measurement probe in response to a load from an outside.
