A base station allocates at least one of a plurality of wireless channels included in a used frequency hand to a mobile station. The base station includes: a used frequency hand determination unit for determining at least a part of a predetermined frequency band as the used frequency band; a message generation unit for generating a control message including used frequency band information which is placed in a predetermined position and which indicates the determined used frequency hand, and channel allocation information which has a size corresponding to a bandwidth of the used frequency band and which indicates the wireless channel to be allocated to the mobile station; and a modem and a wireless communication unit for transmitting the generated control message to the mobile station.