Certain mechanisms of a plating apparatus address problems associated with interaction between plating solutions or other processing solutions and the components of the plating apparatus. The drive portion includes a first drive section for causing a first current to flow to drive the element, and a second drive section for causing a second current smaller than the first current to flow to drive the element. The invention uses a second pulse generating circuitry having a resonator element having an input and an output, a reference signal in the form of a second pulse train having a second pulse repetition frequency which differs from the first pulse repetition frequency by a predetermined frequency difference.