Disclosed is a carrier management method for use in a carrier aggregation environment of a mobile communication system. In the method, a base station is configured to transmit a deactivation message for a secondary carrier to a terminal and change the secondary carrier to a deactivation state after a predetermined time from the transmission of the deactivation message. The terminal receives the deactivation message transmitted by the base station, and changes the secondary carrier to the deactivation state after a predetermined time from the transmission of the deactivation message. As the predetermined time, a predefined value may be used to prevent inconsistency of secondary-carrier state information that is managed by the base station and the terminal. If the carrier state management information is used, it is possible to prevent inconsistency of secondary-carrier states that are managed by the base station and the terminal and solve problems due to the inconsistency.