An image synthesis apparatus includes: an image selection section adapted to select two or more three-dimensional images to be synthesized from among a plurality of three-dimensional images; an order determination section adapted to determine, based on parallax amounts of the selected three-dimensional images, a synthesis order representative of an order in which the selected three-dimensional images are to be synthesized; an image synthesis section adapted to synthesize the selected three-dimensional images in accordance with the synthesis order; and a control section adapted to control the image selection section, the order determination section and the image synthesis section in response to an operation of a user.