This study has proposed a method of frictional reduction and lubricity improvement for meshed gears, which is based on ultrasonic oscillation. This report describes gear and shaft design using the finite element analysis (FEA), and results of experiments using an ultrasonic actuator. First, the FEA calculated axial and radial amplitude of vibration on the shaft and gear surfaces. A modified gear profile improved the axial amplitude by 50 % as keeping the radial amplitude low. Next, a manufactured gear thermally-inserted to a shaft was oscillated by an ultrasonic transducer excited by two types of driving amplifiers. Measurement with laser Doppler vibrometer demonstrated that the axial and radial amplitudes of vibration were 1.3 μm(p-p) and 0.49 μm(p-p), respectively.