1. An instruction fetch control apparatus having a branch history in which an instruction address of a branch instruction and an address of a branched-to instruction for use when a branch is taken are registered as a set of data for the branch instruction, and a return address stack storing a returned-to instruction address of a subroutine when a subroutine call instruction is completely executed, comprising: an entry designation unit designating, when an instruction fetched from a main storage device and detected as a hit in the branch history is a return instruction of a subroutine, an entry in a plurality of entries in the return address stack as an entry storing a return address of the return instruction, wherein an instruction is fetched using the return address stored in said designated entry.