PURPOSE: To prevent the delay of a restart of a read request inhibited by a fact that store request outstripping is detected.

CONSTITUTION: When store request outstripping of a read request is detected, an address hit signal 131 is outputted to a data request part from an OR gate 130. As a result, a read request is inhibited and stored in a restart processing buffer which is not shot in the figure. Also, store data and store addresses stored in store data registers 101-104 and store address registers 112-115 through selectors 109, 118 are given to a cache memory 120 and sweeping-out of a store buffer is started. Simultaneously, a restart processing instruction 138 is outputted to a cache control part, and the cache control part re-requests a read request in the restart processing buffer to the cache memory 120.