The image data generator 1 produces image data for recording into a holographic stereogram. The image data generator 1 combines a stereo image model being at least a part of a three-dimensional object image prepared in advance with a separately captured image to provide a synthetic image and produces a parallax image train from the synthetic image. The three-dimensional object image prepared in advance and stereo image model being the part of the three-dimensional object are supplied from the 3D image source 4 to the image data generator 1. The image data generator 1 is also supplied with a two-dimensional image separately captured from the photographic unit 5 such as a digital still camera for example.