A prototype three-dimensional tool oscillation system for finishing metal molds, which can oscillate a tool in a figure-8 motion, has been developed. When such a tool motion is used, the lapping direction alternatively changes and consequently a very smooth surface might be achieved in a relatively short time in the presence of a very fine abrasive compound. The developed tool oscillation system consists of three multilayer piezoelectric transducers. The orientation of the tool motion can be changed in three dimensional space. This paper describes the structure of the tool oscillation system, the driving method of the three piezoelectric transducers for oscillating a tool in a figure-8 motion and the measurement results for the tool motions.