A method for sharing a channel in a communication system is disclosed. The method includes receiving scheduling information including information about a channel time reserved by other user devices, and transmitting data through the reserved channel time if a result of performing scanning in the reserved channel time indicates that no interference occurs, wherein the communication system performs communication using beam signals which are directional. If the signals are highly directional, the channel sharing method enables a plurality of user devices to share a channel, thereby increasing the efficiency of channel use.