1. A moving picture encoding method, carried out by a computing system, which generates a predicted image using motion vector information and reference frame(s) information, comprising: in a prediction mode in which prediction mode motion vector information of a current block in a current frame is not to be transmitted to a decoding side: selecting, from among multiple candidate reference frames, a frame(s) to be referenced to in the prediction mode; and determining motion vector information to be used for the current block in the prediction mode, based on whether adjacent blocks adjacent to the current block in a current frame, have a motion vector, wherein both the adjacent blocks and the current block belong to the current frame and the adjacent blocks are encoded earlier than the current block; performing moving picture encoding by generating said predicted image using the reference frame(s) information on said selected reference frame(s) and the motion vector information in said prediction mode; and wherein all of candidate blocks belong to the current frame.