According to an aspect of embodiment, a memory controller for controlling a memory having areas of data unit of K bits, includes a data mapping unit dividing N bits of data, where N is not a multiple of K, into K bits and (N−K) bits, and in regard to L pieces of the data, arranging L K-bit data into L data units, and arranging L (N−K)-bit data into M (M=L×(N−K)/K) data units by packing; and an access control unit access-controlling the memory to access the L K-bit data as L data units, and access-controlling the memory to access the packed L (N−K)-bit data as M data units.