A moving picture coding/decoding device includes an image memory/prediction image generator (108) for selecting one combination from a plurality of combinations between at least one reference image number prepared in advance and a prediction parameter and generating a prediction image signal (212) according to the reference image number and the prediction parameter of the selected combination. The device uses a variable length encoder (111) to encode orthogonal conversion coefficient information (210) concerning a prediction error signal of the prediction image signal (212) for an input moving picture signal (100), mode information (213) indicating a coding mode , motion vector information (214), and index information (215) indicating a combination of the selected reference image number and the prediction parameter.