A measurement probe is detachably connected to a bio-optical measurement apparatus which performs optical measurement on body tissue. The measurement probe includes two illumination fibers configured to irradiate the body tissue with low coherent light having a short spatial coherence length, and three or more light-receiving fibers configured to receive scattered light at multiple angles. The three or more light-receiving fibers are arranged on a perpendicular bisector of a line segment connecting centers of the two illumination fibers at a distal end surface of the measurement probe.