1. An image synthesizing apparatus comprising: a stereoscopic image input section configured to input a stereoscopic image; a visual information input section configured to input visual information to be added to the stereoscopic image; and a synthesizing section configured to synthesize the visual information and the stereoscopic image, wherein the visual information is synthesized over a portion in the stereoscopic image at a coordinate that will not be used for stereoscopic representation and will be used when the stereoscopic image is displayed as a 2-dimensional image.