According to an embodiment of the present invention, a method for transmitting Device-to-Device (D2D) data by a User Equipment (UE) in a wireless communication system, the method comprising: determining a bitmap to be applied to a subframe pool for data transmission from a subframe indicator bitmap; determining a set of subframes to transmit D2D data by using the bitmap to the subframe pool for data transmission; and transmitting D2D data in a subframe included in the determined subframe set, wherein a set of values available as k being the number of 1s in the subframe indicator bitmap are changed according to a Uplink/Downlink (UL/DL) configuration set to which a UL/DL configuration configured for the UE belongs.