A vehicle-mounted communication device includes wireless units 3a and 3b that switch a frequency that performs wireless communication with antennas 2a and 2b between a frequency for wireless communication for ITS and a frequency for wireless LAN communication, a parking determination unit 6 that determines whether or not a vehicle is parked, a parking position storage unit 6a that stores as a parking position a position where it is determined that the vehicle is parked by the parking determination unit 6, and a wireless control unit 4 that controls the wireless units 3a and 3b to perform the wireless communication for ITS with the antennas 2a and 2b when the vehicle is running, and switch the wireless communication for ITS or the wireless LAN communication to be performed with the antennas 2a and 2b on the basis of the parking position stored in the parking position storage unit 6a when the vehicle is parked.