To output transportation information at proper sound pressure regardless of the percentage modulation of transportation-information broadcasting and the intensity of radio waves even in the case of changeover to a transportation-information broadcasting mode in an on-vehicle acoustic device.

A sound-pressure adjusting means 131 for an audio processing section 13 is controlled by a microcomputer section 21 when a mode is changed over to the transportation-information broadcasting mode by a transportation- information button 23 for an operating section 22, and the sound pressure of transportation-information broadcasting is adjusted automatically at a reference level and output to an audio amplifying section 14 when the sound pressure received by a radio reception section 12 differs from the fixed reference level.