Transport of electrons through a Au nanodot has been observed under a nanomechanical vibration of a Au nanodot on cantilever that consists of scanning tunneling microscopy probe/vacuum/Au nanodot/cantilever. In the probe tunneling current-distance characteristics, a constant probe current of 2ef has been observed as a plateau region, where f is an eigenfrequency of the cantilever of 86 MHz. The authors discuss this quantized tunneling current in relation to one by one single-electron transport per cycle of operation in nanomechanical Coulomb blockade shuttle.