Abstract: A concrete vibrator apparatus is described for use in conjunction with a concrete finishing machine that is movable longitudinally along a roadway. The finishing machine includes a finishing unit engageable with the surface of the concrete and movable transversely across the roadway, a supporting frame mounted to and extending forwardly and outwardly from the movable finishing unit, and a vibrator assembly mounted to the supporting frame. The vibrator assembly includes first and second vibrator units, with each of the vibrator units being independently movable between a downwardly position wherein the vibrator unit extends into and below the surface of the concrete and an upwardly position wherein the vibrator unit is out of contact with the surface of the roadway. A control mechanism is described for controlling the selective movement of the vibrator units and the rate of vibration of the vibrator units.