The present document relates to a method for determining whether a corresponding medium (for example, a channel) is reusable so as to improve a space reuse rate in a wireless communication system, particularly, a wireless LAN system, and an apparatus for the same. To this end, a station receives a wireless LAN signal through a specific wireless medium, compares the received signal intensity of the wireless LAN signal with a CCA level selected from between a first CCA level and a second CCA level lower than the first CCA level according to the type of the received wireless LAN signal, determines that the corresponding wireless medium is usable if the received signal intensity is lower than the selected CCA level, and can use the wireless medium in a signal transmission.