PURPOSE: To obtain a three-dimensional image which is short in arithmetic time and close to a natural image and has no influence of the defocusing of a body behind a body on a focal plane upon an image of the latter body by giving respective pixels defocusing effects corresponding to the distances from the focal plane.

CONSTITUTION: Depth information Z regarding the distance from a view point 10 to each body and a radius R of defocusing which corresponds to the distance from the focal plane to each body and allows the defocusing effects are prepared for each of pixels constituting an original image 2, and a weighting filter 11 which determines the pixel value of an aimed pixel 13 by using said values is obtained. The weighting filter 11 performs arithmetic processing so that peripheral pixels which are larger in depth-directional distance than the aimed pixel and peripheral pixels in a place larger than the defocusing radius are not affected.