A measurement probe 3, which is detachably connected to a biological optical measurement apparatus 2 that performs an optical measurement on body tissue, includes: an illumination fiber 31 that irradiates the body tissue with illumination light a first detection fiber 32 that detects a return light of at least one of illumination light reflected from the body tissue and illumination light scattered from the body tissue a second detection fiber 33 and a third detection fiber 34. A detection area, at a measurement position of the body tissue, detected by each of the first detection fiber 32, the second detection fiber 33, and the third detection fiber 34 is included in an illumination area at the measurement position of the body tissue illuminated by the illumination fiber 31.
