Abstract: An easily adjusted vibratory device useful, for example, on soil compacting vibratory rollers. One or more mass elements are supported eccentrically on a rotating shaft. The mass elements are pivotal about a pivotal axis or shaft perpendicular to the rotating shaft. Pivoting the mass elements during rotation of the shaft moves the center of gravity of the mass elements toward or away from the rotating shaft and thereby continuously alters the magnitude of the centrifugal force acting on the mass elements to cause vibration. The mass elements are formed, with respect to the pivotal shaft, to minimize the force necessary to pivot the elements by maintaining the moment arms from the axis of the pivotal shaft to the centrifugal force resultant at or near zero. In a specific embodiment the rotating shaft is cylindrical, the mass elements and pivotal shaft are supported within the rotating shaft.