A method for receiving a PDCCH by a terminal in a mobile communication system may comprise the steps of: receiving a first PDCCH including first DCI from a base station through a first PDCCH search space; and receiving a second PDCCH including second DCI from the base station through a second PDCCH search space, wherein the first DCI and second DCI are for scheduling the same PDSCH for the same TB or TBs associated with the same HARQ process, are for scheduling different PDSCHs for the same TB or TBs associated with the same HARQ process, or are for scheduling different PDSCHs for different TBs or TBs associated with different HARQ processes. In addition, the first DCI and second DCI may be received from the base station within a time window.