An image synthesizing apparatus which generates, from plural images with differing resolutions and lighting conditions, a synthesized image in which the resolution of the original image is improved and the lighting conditions match those of the original image. The image synthesizing apparatus includes: a camera which acquires an original image and plural reference images; a reference image conversion unit; a coefficient calculation unit which calculates a conversion coefficient used in performing linear combination on the plural converted reference images and generating an original image; and an image synthesizing unit.