A memory allowing reduction of the period of an external access operation is provided. This memory comprises an access control portion performing an internal access operation on the basis of an external access operation, a refresh control portion performing a refresh operation and a refresh division control portion dividing the refresh operation into a read operation RFRD and rewrite operations RFRS1 and RFRS2. The memory performs the read operation RFRD and the rewrite operations RFRS1 and RFRS2 at least either before or after different internal access operations corresponding to different external access operations respectively.