A medical image-processing apparatus according to embodiments includes processing circuitry. The processing circuitry is configured to acquire image data including a blood vessel of a subject. The processing circuitry is configured to acquire an index value relating to blood flow at each position of the blood vessel by performing fluid analysis of a structure of the blood vessel included in the acquired image data. The processing circuitry is configured to acquire information indicating a display condition of the index value, as switching information to switch a display mode at displaying the index value. The processing circuitry is configured to generate a result image in which pixel values reflecting the index value are assigned in a display mode according to the switching information, for an image indicating a blood vessel of the subject. The processing circuitry is configured to cause a display to display the result image.