To prevent a user from getting out of a car without removing an ETC card from an ETC on-board unit, in the ETC on-board unit for performing automatic toll collection.

The ETC on-board unit 10 provided with an IC card connector 14 to which an ETC card 20 is inserted is provided with: a control unit 18 which is connected to a meter device 31 having a display part 32 and detects an on/off state of an ignition SW 40; and an IC card read part 15 for detecting whether the ETC card 20 is inserted to the IC card connector 14. When the control unit 18 detects that the ignition SW 40 switches from on to off, it determines whether the ETC card 20 is inserted to the IC card connector 14 via the IC card reading part 15 and, when the ETC card 20 is inserted to the IC card connector 14, displays warning information on the display part 32 of the meter device 31.