ON-VEHICLE RADIO APPARATUS AND ON-VEHICLE RADIO COMMUNICATION SYSTEM

PROBLEM TO BE SOLVED: To provide an on-vehicle radio apparatus and on-vehicle radio communication system, capable of achieving relatively easy confirmation of a state of antenna connection even in use of an existing radio LAN module or Bluetooth(R) module.SOLUTION: The on-vehicle radio apparatus includes a directional coupler 108, and the directional coupler 108 is formed in a wiring pattern on a mounting substrate 111 for mounting the directional coupler 108 and is structured so that an inductor component of the wiring pattern forming the directional coupler 108 is a part of an inductor component of an antenna matching circuit of a radio LAN antenna 112 and the on-vehicle radio apparatus.