The present invention groupcasts a groupcast frame in a short period of time by using millimeter wave communication. A communication device equipped with a MAC control circuit for controlling a procedure for discovering a communication partner device and a procedure for determining the best transmission sector, and also equipped with a wireless circuit for transmitting a unicast frame to the communication partner device by using the best transmission sector, wherein the MAC control circuit controls the wireless circuit so as to start a timer for each discovered communication partner device after the procedure for discovering communication partner devices is completed, and transmit a groupcast frame to communication partner devices for which the timer has not finished by using the best transmission sector upon receiving a groupcast frame transmission request from a higher layer before all timers have finished.