A terminal apparatus configured to and/or programmed to perform data communication with a base station apparatus, and perform device-to-device data communication involving no base station apparatus, the terminal apparatus comprising: a first transmission buffer configured to store first transmission data to the base station apparatus; and a second transmission buffer configured to store second transmission data for the device-to-device data communication; and a transmission data control unit configured to and/or programmed to constitute a first buffer status report and a second buffer status report, wherein the first transmission data is prepared in the first transmission buffer of the terminal apparatus, the second transmission data is prepared in the second transmission buffer of the terminal apparatus, and the first buffer status report includes first information on the amount of first transmission data, and the second buffer status report includes second information on the amount of second transmission data; and a transmission unit configured to and/or programmed to report the first buffer status report and the second buffer status report to the base station apparatus using a padding region of an uplink resource allocated to the terminal apparatus, characterized in that in a case where a number of bits of the padding region is smaller than a number of bits that includes the first buffer status report and the second buffer status report and the subheaders thereof, the transmission data control unit is configured to determine that the second buffer status report is changed to be shorter in format; in a case where the number of bits of the padding region is greater than a number of bits that includes the first buffer status report and the subheader thereof, and is smaller than a number of bits that includes the first buffer status report, the second buffer status report, and the subheaders thereof, the transmission data control unit is configured to report to the base station apparatus the first buffer status report and to not report the second buffer status report; and in a case where the number of bits of the padding region is smaller than a number of bits that includes the first buffer status report and the subheader thereof, and is greater than a number of bits that includes the first buffer status report in a short format, the transmission data control unit is configured to report to the base station apparatus the first buffer status report in the short format and to not report the second buffer status report. a first transmission buffer configured to store first transmission data to the base station apparatus; and a second transmission buffer configured to store second transmission data for the device-to-device data communication; and a transmission data control unit configured to and/or programmed to constitute a first buffer status report and a second buffer status report, wherein the first transmission data is prepared in the first transmission buffer of the terminal apparatus, the second transmission data is prepared in the second transmission buffer of the terminal apparatus, and the first buffer status report includes first information on the amount of first transmission data, and the second buffer status report includes second information on the amount of second transmission data; and a transmission unit configured to and/or programmed to report the first buffer status report and the second buffer status report to the base station apparatus using a padding region of an uplink resource allocated to the terminal apparatus, characterized in that in a case where a number of bits of the padding region is smaller than a number of bits that includes the first buffer status report and the second buffer status report and the subheaders thereof, the transmission data control unit is configured to determine that the second buffer status report is changed to be shorter in format; in a case where the number of bits of the padding region is greater than a number of bits that includes the first buffer status report and the subheader thereof, and is smaller than a number of bits that includes the first buffer status report, the second buffer status report, and the subheaders thereof, the transmission data control unit is configured to report to the base station apparatus the first buffer status report and to not report the second buffer status report; and in a case where the number of bits of the padding region is smaller than a number of bits that includes the first buffer status report and the subheader thereof, and is greater than a number of bits that includes the first buffer status report in a short format, the transmission data control unit is configured to report to the base station apparatus the first buffer status report in the short format and to not report the second buffer status report.