An audio device arrangement structure for a motorcycle is configured and arranged to provide high-quality sound output. The audio device arrangement structure serves to mount an audio device, which includes an audio unit, an amplifier and at least one speaker, for a motorcycle. The audio unit is mounted at the front of the vehicle inside a top cover, between the top cover and the air cleaner. The amplifier is provided separately from the audio unit, and is arranged at the rear of the vehicle in the inside of a housing provided at a rear portion of a rear fender. The amplifier is supported on the housing by rubber bushings, to isolate the amplifier from vibrations of the vehicle body.