Disclosed is a method for transmitting, by a first station, a frame in a wireless LAN system, and a station device therefor. To this end, a station generates a radio frame for a second type station comprising a frame portion for a first type station and a frame portion for the second type station, wherein the frame portion for the second type station comprises a signal field, a short training field (STF), a long training field (LTF), and a data field, the LTF having a symbol duration that is two or four times longer than the symbol duration of the frame portion for the first type station, and the signal field comprising information about the symbol duration of the LTF for the second type station.