A memory device is configured as single chip to achieve routing control, bandwidth control, traffic monitoring, buffering, and access control of network functions. The memory device includes a search unit that includes a first memory unit and performs a search operation by searching, from the first memory unit, a piece of data corresponding to an input search key, a statistical information processing unit that includes a second memory unit that stores statistical information including the input search key, with which the piece of data has been successfully searched by the search unit, and an address of the piece of data in the first memory unit, and an arithmetic operation unit that updates the statistical information when the search unit successfully searches the pieces of data corresponding to the input search key.