The present invention relates to a wireless communication system and, more particularly, to an improved scanning method and apparatus in a wireless LAN system. A method by which an access point (AP) supports the scanning of a station (STA) in a wireless LAN system, according to one embodiment of the present invention, includes the steps of: receiving, by the AP which supports first and second channel widths, a probe request frame in the first channel width or second channel width from the STA; and transmitting a probe response frame, which responds to the probe request frame, to the STA. When the probe request frame is received in the first channel width, the probe response frame can be transmitted in said first channel width. When the probe request frame is received in the second channel width, the probe response frame can be transmitted in said second channel width.