Provided is a method of occupying a channel in a wireless communication system that supports an unlicensed band. The method comprising detecting an earlier point among a first point at which transmission of a first subframe in a first channel is completed and a second point at which a busy state of a second channel is terminated. The method further comprising determining a type of a second subframe based on at least one of a result of the detecting or first transmit power for the first channel, transmitting the second subframe of the determined type in the first channel after transmission of the first subframe is completed, and transmitting a third subframe in the first channel and a fourth subframe in the second channel, after transmission of the second subframe is completed.