A memory management unit including: a first memory portion in which a memory area is allocated; a memory allocation processor for allocating and releasing a memory area in the first memory portion; a second memory portion for storing reserve area information regarding a memory area which should be reserved in an upper or lower address area of the first memory portion; and a learning reservation processor for monitoring the memory area allocation and release executed in the memory portion, allowing the information regarding the memory area which fragments the first memory portion to be stored in the second memory portion as the reserve area information. The learning reservation processor gives an instruction to the memory allocation processor to reserve a memory area according to the reserve area information, and the memory allocation processor reserves the memory area according to the reserve area information.