1. A moving picture decoding method, which generates a predicted image using information on motion vectors and information on reference images, the moving picture decoding method having multiple prediction modes including a mode without motion vector decoding, comprising: a step of selecting a frame(s) to be referenced to in the prediction of each prediction direction in the prediction mode from among multiple candidate reference frames; and a step of selecting motion vector information used in the prediction mode, wherein at said step of selecting motion vector information when (all) candidate blocks adjacent to a current block are located outside of the screen, a zero vector is selected; and moving picture decoding is performed by generating said predicted image using the information on said selected reference frame and the information on said selected motion vectors in said prediction mode.