A method and device for dynamically allocating resources to a frequency band of a short transmission time interval (TTI) in a wireless communication system is provided. Specifically, a plurality of first downlink channels and a second downlink channel included in a subframe corresponding to one TTI are received, wherein the plurality of first downlink channels are received during sTTIs and the second downlink channel is received during the TTI. The plurality of first downlink channels are sequentially received. The plurality of first downlink channels are demodulated using control information included in a downlink control information (DCI) used for the second downlink channel and an RRC message. The control information and RRC message indicate frequency resources for the plurality of first downlink channels.