An RF unit broadcasts a packet signal, and receives a packet signal broadcasted from another terminal apparatus. A processing unit generates a packet signal to be broadcasted and processes a received packet signal. A mode setting unit selects a first mode or a second mode as a broadcast mode. The RF unit sets first transmission power in case of the first mode and sets second transmission power lower than the first transmission power in case of the second mode. The processing unit includes an identification number uniquely allocated to the present terminal apparatus in a packet signal in case of the first mode, and includes an identification number commonly allocated to a system of terminal-to-terminal communication in a packet signal in case of the second mode.