A method for transmitting data from a station (STA) device in a wireless LAN (WLAN) system, according to one embodiment of the present invention, comprises the steps of: generating a physical protocol data unit (PPDU) including a physical preamble, which includes a legacy preamble and a high efficiency-long training field (HE-LTF), and a data field; and transmitting the PPDU, wherein the data field is transmitted at four times (4×) the inverse discrete Fourier transform (IDFT)/discrete Fourier transform (DFT) cycle of the legacy preamble, the HE-LTF is a 4×HE-LTF or a 2×HE-LTF which is respectively transmitted at the four times or two times (2×) the IDFT/DFT cycle of the legacy preamble, and wherein pilot tones of the HE-LTF may be inserted only into subcarriers having an even number of indexes from among subcarriers to which the 4×HE-LTF is mapped.