1. A video coding device comprising: a detecting unit configured to detect a foreground region, a background image and a shadow region reflected on the background image by the foreground region in an input picture, the detecting unit includes a shape information generating unit configured to generate shape information of the foreground region; a shadow information compressing unit configured to perform a compression process to compress the information quantity of the shadow region, the shadow information compressing unit includes a specifying unit configured to specify a relative positional relationship between the foreground region and the shadow region, and a computing unit configured to obtain luminance variation information indicating a luminance variation of the shadow region relative to the background image; and a coding unit configured to code the foreground region, the background image and the information on the shadow region subjected to the compression process, the coding unit codes the shape information, information of the relative positional relationship and the luminance variation information.