An in-vehicle sound control system structured so that sound sources, a vehicle speed detection unit for detecting a vehicle running speed, and an acoustic reproduction apparatus are connected to in-vehicle communications network. The in-vehicle sound control system controls, in accordance with a vehicle speed signal transmitted from the vehicle speed detection unit, a reproduction acoustic signal. The acoustic reproduction apparatus switches, in accordance with a plurality of inputted sound sources and media information of a sound source, a control amount to sound control section determined based on a vehicle speed signal. In this manner, such an in-vehicle sound control system is provided that can provide an optimal automatic sound control for human ears even when the medium is exchanged or when a channel for a sound source in the medium is switched to another channel.