A plurality of address conversion circuits are provided for memory cores respectively, and convert logical address data supplied from outside to physical address data. In an interleave operation, the address conversion circuits output the logical address data as the physical address data without converting the logical address data when a first memory core is to be accessed earlier than a second memory core, whereas output address data obtained by adding a certain value to the logical address data as the physical address data when the second memory core is to be accessed earlier than the first memory core.