A terminal device that communicates with a base station apparatus by using a plurality of cells of a 3GPP radio communication system, the terminal device comprising: a reception unit that receives a first physical downlink control channel, PDCCH, with a first downlink control information, DCI, format and a second PDCCH with a second DCI format, and a higher layer signal from the base station apparatus, the first DCI format being used for scheduling a single physical downlink shared channel, PDSCH, in a single serving cell, the second DCI format indicating respective uplink-downlink, UL-DL, configurations for a plurality of serving cells, the higher layer signal indicating a radio network temporary identifier, RNTI, a monitoring configuration for monitoring another second PDCCH with a cyclic redundancy check, CRC, parity bit scrambled by the RNTI, an index corresponding to a serving cell and used to determine a UL-DL configuration for the serving cell from the respective UL-DL uplink-downlink configurations, and a control information element for activating or deactivating a secondary cell; a configuring unit that determines a subframe to monitor another second PDCCH, the subframe specified by a periodicity T and an offset corresponding to the monitoring configuration; and sets one primary cell and at least one secondary cell as the serving cells; characterized in that the configuring unit activates or deactivates the at least one secondary cell based on the control information element; in a case where any of the serving cells are activated, the reception unit monitors another second PDCCH which indicates at least the UL-DL configuration for the serving cell corresponding to the index, in a common search space for the primary cell, in the determined subframe, in a second case where all of the serving cells corresponding to the index are deactivated, the reception unit does not monitor another second PDCCH, in a third case where another second PDCCH is detected in the determined subframe, a UL-DL configuration for the periodicity T in the serving cell is given by the second DCI format in the detected second PDCCH for the serving cell, and the periodicity T is 10 milliseconds, 20 milliseconds, 40 milliseconds, or 80 milliseconds. a reception unit that receives a first physical downlink control channel, PDCCH, with a first downlink control information, DCI, format and a second PDCCH with a second DCI format, and a higher layer signal from the base station apparatus, the first DCI format being used for scheduling a single physical downlink shared channel, PDSCH, in a single serving cell, the second DCI format indicating respective uplink-downlink, UL-DL, configurations for a plurality of serving cells, the higher layer signal indicating a radio network temporary identifier, RNTI, a monitoring configuration for monitoring another second PDCCH with a cyclic redundancy check, CRC, parity bit scrambled by the RNTI, an index corresponding to a serving cell and used to determine a UL-DL configuration for the serving cell from the respective UL-DL uplink-downlink configurations, and a control information element for activating or deactivating a secondary cell; a configuring unit that determines a subframe to monitor another second PDCCH, the subframe specified by a periodicity T and an offset corresponding to the monitoring configuration; and sets one primary cell and at least one secondary cell as the serving cells; characterized in that the configuring unit activates or deactivates the at least one secondary cell based on the control information element; in a case where any of the serving cells are activated, the reception unit monitors another second PDCCH which indicates at least the UL-DL configuration for the serving cell corresponding to the index, in a common search space for the primary cell, in the determined subframe, in a second case where all of the serving cells corresponding to the index are deactivated, the reception unit does not monitor another second PDCCH, in a third case where another second PDCCH is detected in the determined subframe, a UL-DL configuration for the periodicity T in the serving cell is given by the second DCI format in the detected second PDCCH for the serving cell, and the periodicity T is 10 milliseconds, 20 milliseconds, 40 milliseconds, or 80 milliseconds.