The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for transmitting uplink control information where a plurality of cells are configured, and comprises: a step for receiving one or more PDCCH; a step for generating reception response information corresponding to the one or more PDCCH; and a step for transmitting through PUCCH the reception response information in a subframe, wherein the reception response information is transmitted using a PUCCH resource provided in advance by an upper layer signaling when only one PCell PDCCH is detected and the predetermined conditions are met, and is transmitted using a PUCCH resource linked to an index of a resource that makes up the PCell PDCCH when only one PCell PDCCH is detected and the predetermined conditions are not met.