A radio terminal (1) is configured in such a way that, when the radio terminal (1) receives a downlink signalling message including an information element (641) indicating that a first UL control channel (622) is to be configured in a first secondary cell (SCell) (602) that has already been added as an SCell in a carrier aggregation, where the first UL control channel (622) is to be used to transmit uplink (UL) control information for at least one SCell (602, 603) including the first SCell (602), the radio terminal (1) deactivates one or more SCells (602, 603) in an activated state among the at least one SCell (602, 603).