A method by which a station (STA) operates in a wake up receiver (WUR) mode in a wireless LAN (WLAN) system, according to one embodiment of the present invention, comprises the steps of: entering into the WUR mode by turning off a WLAN transceiver of the STA and turning on a WUR receiver of the STA; starting a timer by entering into the WUR mode; and turning on the WLAN transceiver of the STA when the timer is completed or a wake-up signal for waking up the STA is detected through the WUR receiver, wherein the timer can indicate the remaining time for which the STA can maintain the WUR mode until the STA receives a predetermined WUR signal for confirming the presence of an associated access point (AP).