A control device (11, 110) being adapted to manage a communication terminal (12-1 to 12-3, 120-1 to 120-3) within a communication area (15, 150) and to communicate with the communication terminal (12-1 to 12-3, 120-1 to 120-3) in an active period (52, 52-1 to 52-3, 520, 520-1 to 520-3) by using a plurality of predetermined frequency channels, the control device (11, 110) comprising: a first beacon packet generation section being adapted to generate a first beacon packet (541, 541-1 to 541-3) which includes information indicating the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3) and one or more candidate channels to which a use channel is possibly changed from a currently used channel; a first beacon packet transmission section being adapted to transmit the first beacon packet (541, 541-1 to 541-3) to the communication terminal (12-1 to 12-3, 120-1 to 120-3), at the beginning of the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3); characterized in a second beacon packet generation section being adapted to determine whether or not the use channel is to be changed, based on a state of communication with the communication terminal (12-1 to 12-3, 120-1 to 120-3) in the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3) indicated by the transmitted first beacon packet (541, 541-1 to 541-3); and being adapted to generate a second beacon packet (542, 542-1 to 542-3) which includes information of whether or not the use channel is to be changed; a second beacon packet transmission section being adapted to transmit the second beacon packet (542, 542-1 to 542-3) to the communication terminal (12-1 to 12-3, 120-1 to 120-3), at the end of the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3); and a channel change processing section that: when the second beacon packet generation section determines that the use channel is to be changed, is adapted to change the use channel to a change channel different from the currently used channel, after the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3) ends and before a next active period (52, 52-1 to 52-3, 520, 520-1 to 520-3) starts; and, when the second beacon packet generation section determines that the use channel is not to be changed, is adapted to maintain the currently used channel as the use channel. a first beacon packet generation section being adapted to generate a first beacon packet (541, 541-1 to 541-3) which includes information indicating the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3) and one or more candidate channels to which a use channel is possibly changed from a currently used channel; a first beacon packet transmission section being adapted to transmit the first beacon packet (541, 541-1 to 541-3) to the communication terminal (12-1 to 12-3, 120-1 to 120-3), at the beginning of the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3); characterized in a second beacon packet generation section being adapted to determine whether or not the use channel is to be changed, based on a state of communication with the communication terminal (12-1 to 12-3, 120-1 to 120-3) in the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3) indicated by the transmitted first beacon packet (541, 541-1 to 541-3); and being adapted to generate a second beacon packet (542, 542-1 to 542-3) which includes information of whether or not the use channel is to be changed; a second beacon packet transmission section being adapted to transmit the second beacon packet (542, 542-1 to 542-3) to the communication terminal (12-1 to 12-3, 120-1 to 120-3), at the end of the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3); and a channel change processing section that: when the second beacon packet generation section determines that the use channel is to be changed, is adapted to change the use channel to a change channel different from the currently used channel, after the active period (52, 52-1 to 52-3, 520, 520-1 to 520-3) ends and before a next active period (52, 52-1 to 52-3, 520, 520-1 to 520-3) starts; and, when the second beacon packet generation section determines that the use channel is not to be changed, is adapted to maintain the currently used channel as the use channel.