A tuning structure of a sound mixer is disclosed to include a switch set, formed of sliding switches with a respective switching lever, a face panel, which has sliding slots arranged in parallel for the passing of the switching levers of the switch set, a track set, which is mounted in between the switch set and the face panel and has pairs of ribs for guiding movement of the switching levers of the sliding switches stably along the sliding slots of the face panel, and tuning keys respectively fastened to the switching levers of the switch set and suspending above the face panel.