A blood vessel function inspecting apparatus including blood flow velocity distribution measuring portion for measuring a blood flow velocity distribution within a blood vessel in a non-invasion manner with ultrasonic waves before releasing of the blood vessel from a blood flow obstruction or after a blood vessel diameter measuring time period; viscosity-shear rate relationship calculating portion; and blood shear stress calculating portion for measuring a blood flow velocity within the blood vessel, concurrently with the measurement of a change ratio of the diameter of the blood vessel within the predetermined blood vessel diameter measuring time period after releasing of the blood vessel from the blood flow obstruction, and calculating a blood shear stress on the basis of a measured blood flow velocity, and according to a viscosity-shear rate relationship.