A terminal device for performing terminal-to-terminal communication in which wireless communication with a relay terminal device that is in a state in which wireless communication with a first base station device is able to be executed is performed directly without an intervention of the first base station device , and is able to execute wireless communication with a second base station device (40; 50) capable of communicating with the first base station device , the terminal device comprising: communication means for receiving, from a base station device, search information to search for the relay terminal device ; and control means for executing control to search for the relay terminal device using the search information received by the communication means ; characterised in that the communication means is configured to receive, as the search information, from the second base station device (40; 50), search information notified from the first base station device to the second base station device (40; 50), the search information including a search signal transmission period, a transmission time limit timer concerning a time limit of search signal transmission, radio resource information to be waited, and a waiting time limit timer concerning a time limit of waiting; and the control means is configured to control the transmission of a search signal in accordance with the transmission period and the transmission time limit timer, and to wait for a response signal to the search signal in accordance with the radio resource information and the waiting time limit timer, wherein if the second base station device (40; 50) is in a state in which communication with the first base station device cannot be executed, the control means is configured to transmit the search signal to the relay terminal device only when one or both of a condition that the terminal-to-terminal communication with the relay terminal device is permitted in advance and a condition that an appropriate connection destination cell does not exist are met. communication means for receiving, from a base station device, search information to search for the relay terminal device ; and control means for executing control to search for the relay terminal device using the search information received by the communication means ; characterised in that the communication means is configured to receive, as the search information, from the second base station device (40; 50), search information notified from the first base station device to the second base station device (40; 50), the search information including a search signal transmission period, a transmission time limit timer concerning a time limit of search signal transmission, radio resource information to be waited, and a waiting time limit timer concerning a time limit of waiting; and the control means is configured to control the transmission of a search signal in accordance with the transmission period and the transmission time limit timer, and to wait for a response signal to the search signal in accordance with the radio resource information and the waiting time limit timer, wherein if the second base station device (40; 50) is in a state in which communication with the first base station device cannot be executed, the control means is configured to transmit the search signal to the relay terminal device only when one or both of a condition that the terminal-to-terminal communication with the relay terminal device is permitted in advance and a condition that an appropriate connection destination cell does not exist are met. <EOS>