A dedicated short-range communication on-vehicle apparatus easily attachable on a wind shield of the motor vehicle includes an antenna, a radio module, a data processing unit and others contained in a single box-like housing. The antenna (8) has directivity in a predetermined orientation. The radio module (10) performs transmission/reception of radio wave with road-side radio equipment through the antenna (8). The data processing unit (11) processes data transferred through the radio module (10). The box-like housing (4) houses the antenna (8), the radio module (10) and the data processing unit (11) en bloc. The box-like housing (4) is fixedly attached onto a windshield (3) of the motor vehicle at a mounting plate (4a) of the housing (4) on the antenna radiation side by an adhesive member (30). A radio wave aperture portion of the mounting plate (4a) is made of a radio wave transmissible material.