In a wireless communication system having a wireless base station, wireless terminal stations belonging to a first group which performs wireless communication while sharing different frequency channels, and wireless terminal stations belonging to a second group which performs wireless communication by using one frequency channel, a first communication period and a second communication period is alternately repeated. In this system, a wireless terminal station belonging to the first or the second group communicates with the wireless base station by using a first frequency channel in the first communication period. Direct communication between two wireless terminal stations belonging to the first group by using a second frequency channel without through the wireless base station is performed in the first communication period. Then, a wireless terminal station belonging to the first group communicates with the wireless base station by using both the first and the second frequency channels.