PURPOSE: To eliminate unnecessary writing to a cash memory by deciding on whether writing from a main storage device to the cash memory is performed or not in response to a write indication queuing indication and an indication for showing whether a branch instruction has been executed or not.

CONSTITUTION: When a host address of an actual address from the advance control part 2 of a processor 10 does not coincide with a host address of an aclual address of a block in a cash memory (CM), a comparing circuit 5 sends a block transfer request to a main storage device (MM)6 and a bus 26 to a CM write indication queuing circuit 7 is held at a high level. On the other hand, a bus 22 is held at the high level in response to a request to read a branch instruction in a control part 2 to apply a high-level write indication queuing output from the circuit 7 to a CM write control circuit 8. In this state, when a branch success or failure indication is applied from starting execution control part 1, the circuit 8 responds to each indication to decide on whether writing is performed or not and only when the success in branching is obtained, writing from the MM 6 to the CM 4 is performed. Thus, information processing performance is improved without any unnecessary writing.