A method for transmitting a signal in an unlicensed band in a wireless communication system according to one embodiment of the present invention is performed by a transmission node and comprising the steps of: receiving information about additional channel sensing from a center node; performing channel sensing for signal transmission during a first time period; when the channel is in an unoccupied state as a result of the channel sensing, performing additional channel sensing during a second time period immediately following the first time period according to the information about the additional channel sensing, the length of the second time period being determined according to a transmission priority level of the transmission node; and when the channel is in an unoccupied state as a result of the additional channel sensing, transmitting a signal.