Providing a parameter calculation unit that calculates parameters representing medical functional information for pixel positions of the medical image, wherein the upper and lower limit values of the parameter medically represent the same functional information and whose value changes cyclically between these values, an interpolation parameter calculation unit that obtains, for a pixel position for which the parameter is not calculated, a parameter by interpolation, the unit calculating a parameter obtained by the interpolation using a cyclic function in which the interpolation direction differs according to the difference between the parameters calculated for two pixel positions, a display color group storage unit that includes a color group in which the same color corresponds to the upper and lower limit values of the parameter and whose color changes with the magnitude of the parameter, and a mapping unit that maps the parameters based on the color group.