An image synthesizing device is operatively coupled to a plurality of cameras to accurately express the color and brightness of a synthesized image photographed. The image synthesizing device is configured to synthesize the images of the cameras by selecting with respect to an observation point on a surface being photographed the camera positioned closest to the observation point, designating the color and brightness values of the observation point photographed by that camera as the color and brightness values of the observation point, and conducting the same processing for the entire surface being photographed. Thus, among the cameras, the image synthesizing device selects the camera that is closest to the observation point and uses the color and brightness values of that camera. This arrangement results in selecting a camera that photographs a small area of the photographed surface per unit pixel. Consequently, a synthesized image having good color and brightness precision is obtained.