A moving image composing system for displaying reduced and encoded images at arbitrary positions on a multi-image raster. The moving image composing system comprises a moving image reducing unit for reducing a moving image inputted, a moving image encoding unit for encoding the reduced moving image to produce an encoded moving image, an accumulating unit for storing and accumulating the encoded image, and a moving image composing unit for combining more-than-one encoded moving images accumulated to produce a multi-image combined moving image. The moving image encoding unit performs the encoding processing to facilitate the change of positional information the reduced moving image has, in consideration with the case that the change of the position information occurs due to the disposition of the reduced moving image at its combination. When there is a need to change the positional information of the reduced moving image due to the combination processing, the moving image composing unit changes the positional information to positional information required for the combination processing.