PURPOSE: To provide the information processor which is reduced in power consumption without any decrease in processing speed.

CONSTITUTION: An instruction buffer for making an advanced read of an instruction is incorporated in a central processor 100. Plural memory banks 130 and 150 are composed of RAMs 120 and 140 which differ in power consumption and data are stored in the memory banks, one by one, in order from the memory bank with large power consumption. When the memory bank 130 having the larger power consumption between the memory banks 130 and 150 is accessed, the data stored in the other memory bank 150 are accessed by a memory control means 110 at the same time.