A base station apparatus comprising: a resource allocation information generating section configured to generate uplink resource allocation information relating to a resource allocation of an uplink component carrier and downlink resource allocation information relating to a resource allocation of each of a plurality of downlink component carriers including a first downlink component carrier and a second downlink component carrier; a padding section configured to add zeros, when a number of uplink information bits necessary to transmit the uplink resource allocation information and a number of downlink information bits necessary to transmit first downlink resource allocation information which is to be transmitted using the first downlink component carrier are different, to a smaller one of the uplink resource allocation information and the first downlink resource allocation information until a payload size of the smaller one equals to a payload size of the other; a CRC bits adding section configured to add Cyclic Redundancy Check, CRC, bits, based on the payload size, to the uplink resource allocation information and the first downlink resource allocation information output from the padding section; and a transmitting section configured to transmit a downlink control signal for the first downlink component carrier to a certain terminal apparatus, the downlink control signal including the uplink resource allocation information and the first downlink resource allocation information; characterized in that: the transmitting section is further configured to transmit another downlink control signal for the second downlink component carrier to the certain terminal apparatus, the another downlink control signal including a second downlink resource allocation information and not including the uplink resource allocation information for the certain terminal apparatus. a resource allocation information generating section configured to generate uplink resource allocation information relating to a resource allocation of an uplink component carrier and downlink resource allocation information relating to a resource allocation of each of a plurality of downlink component carriers including a first downlink component carrier and a second downlink component carrier; a padding section configured to add zeros, when a number of uplink information bits necessary to transmit the uplink resource allocation information and a number of downlink information bits necessary to transmit first downlink resource allocation information which is to be transmitted using the first downlink component carrier are different, to a smaller one of the uplink resource allocation information and the first downlink resource allocation information until a payload size of the smaller one equals to a payload size of the other; a CRC bits adding section configured to add Cyclic Redundancy Check, CRC, bits, based on the payload size, to the uplink resource allocation information and the first downlink resource allocation information output from the padding section; and a transmitting section configured to transmit a downlink control signal for the first downlink component carrier to a certain terminal apparatus, the downlink control signal including the uplink resource allocation information and the first downlink resource allocation information; characterized in that: the transmitting section is further configured to transmit another downlink control signal for the second downlink component carrier to the certain terminal apparatus, the another downlink control signal including a second downlink resource allocation information and not including the uplink resource allocation information for the certain terminal apparatus. the transmitting section is further configured to transmit another downlink control signal for the second downlink component carrier to the certain terminal apparatus, the another downlink control signal including a second downlink resource allocation information and not including the uplink resource allocation information for the certain terminal apparatus.