An image processing device and an image processing method for generating a celestial sphere image are provided such that the pixels near the poles of the sphere are kept from increasing in density when the image is mapped to the sphere surface. An encoder encodes, with respect to an omnidirectional image generated by equidistant cylindrical projection to include a top image, a middle image, and a bottom image in a vertical direction, the middle image into an encoded stream at a high resolution, and the top image and the bottom image into encoded streams at a resolution lower than the high resolution in systems including image display systems.