According to an embodiment of the present specification, a method of transmitting a frame in a wireless local area network (WLAN) includes: receiving, by a user station (STA), a multi user-request to send (MU-RTS) frame from an access point (AP) to protect transmission for multi-users, wherein the MU-RTS frame includes common information commonly allocated to the multi-users, user-specific information individually allocated to the multi-users, and a control indicator indicating a first operation mode using a first channel and a second channel contiguous to the first channel and a second operation mode using the first channel and a third channel non-contiguous to the first channel; and transmitting, by the user STA, a clear to send (CTS) frame to the AP according to the control indicator in response to the MU-RTS frame.