1. A branch prediction device comprising: a branch prediction information accumulation processing section for storing branch prediction groups in which pieces of branch prediction information regarding a branch command are grouped, and accumulation-processing the branch prediction information; and a pipeline access control section for performing, upon request, processing including first selection control processing for selection-controlling at least one branch prediction group from the branch prediction groups, and second selection control processing for selection-controlling one or a plurality of pieces of the branch prediction information from the branch prediction group selected by the first selection control processing, by pipeline processing, and controlling an access to the branch prediction information accumulation processing section.