Provided are a method and a device for reducing a transmission resource of a control channel in a short TTI in a wireless communication system. Specifically, a plurality of first downlink channels which are received during an sTTI and are included in a subframe corresponding to one TTI, and a second downlink channel received during a TTI are received. Further, information on a resource block used for the plurality of first downlink channels is obtained by using a resource block indicator transmitted to a downlink control channel of a control region comprising the first symbol of a subframe. The plurality of first downlink channels are demodulated by using the information, and the second downlink channel is demodulated by using the downlink control channel.