An on-vehicle DSRC apparatus includes a main body (11) a signal processing unit provided in the main body (11), an external storage medium insertion slot (12), an antenna array (22) electrically connected to the signal processing unit to perform intercommunication with on-road equipment, a mounting member for the antenna array (22), and an antenna angle holding means (20) mounted swingably on said mounting member (11). The antenna angle holding means (20) is so designed as to set the predetermined range of angle such that a proper angle for enabling intercommunication between the on-road equipment and the antenna array (22) within the predetermined communication area. The angle of the antenna array is automatically held at a proper value owing to swinging movement of the antenna angle holding means.