The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for de-configuring a cell from PUCCH resource in a carrier aggregation system, the method comprising: configuring a Secondary Cell (SCell) with Physical Uplink Control Channel (PUCCH) resource; receiving an RRC signaling indicating that the PUCCH resource PUCCH resource is de-configured from the SCell; and de-activating the SCell after the UE de-configures the PUCCH resource from the SCell according to the RRC signaling.