A medical image processing apparatus according to one of present embodiments includes processing circuitry. The processing circuitry is configured to calculate fluid information including a velocity vector based on three-dimensional phase image data in multiple time phases, the three-dimensional phase image data being collected by phase contrast magnetic resonance imaging, and the three-dimensional phase image data representing a fluid flowing through a lumen. The processing circuitry is configured to identify a wall region of the lumen based on the velocity vector. The processing circuitry is configured to calculate wall shear stress using the wall region and the fluid information.