An image synthesizing apparatus is provided. The image synthesizing apparatus includes: a key image selector, a background selector, a key processor, an image synthesizer, a frame memory, a part designator, and a writing device. In the image synthesizing apparatus, the image signal that has been selected by the key image selector is sent to the key processor, the image signal that has been processed by the key processor is sent to the writing device and written into the frame memory, and image signals read from every storage region of the frame memory are sent to the image synthesizer.