An image processing device is described herein including an information input unit that receives as an input three-dimensional structure information indicating a three-dimensional structure of a heart; and an image generation unit that develops an inner wall of atria and ventricles of the heart indicated by the three-dimensional structure information into a two-dimensional image based on an equal-area projection and generates a developed image interrupted by dividing the two-dimensional image into a front wall, a rear wall, a left wall, and a right wall. The image generation unit maps the three-dimensional structure in the atria and ventricles of the heart indicated in the three-dimensional structure information on the developed image by a projection of expressing the three-dimensional structure with saturation and lightness.