Disclosed are a method and a device for allocating wireless resources in bandwidths of different sizes in a wireless LAN. The method for allocating wireless resources in bandwidths of different sizes in a wireless LAN may comprise steps in which: an AP determines a first resource unit to be allocated to an STA in a first bandwidth; and the AP schedules the first resource unit for the STA, wherein the allocation starting position of the first resource unit allocated in the first bandwidth is configured the same as the allocation starting position of a second resource unit allocated in a second bandwidth, and the allocation starting position of a first guard tone adjacent to the first resource unit may be configured differently from the allocation starting position of a second guard tone adjacent to the second resource unit on the basis of tone shifting.