Instruction cache memory having a plurality of memory (for example, cache WAY), means 3 for storing prediction data of a conditional branch of a branch instruction being taken or not taken and for storing prediction data of memory storing the branch instruction data of the plurality of memory when the prediction is the branch being taken, and means for, when an instruction to be executed is a branch instruction, outputting a read active control signal to the plurality of memories 1 by using two pieces of prediction data obtained from the means by an index corresponding to the branch instruction, are comprised.