This paper presents experimental study and numerical simulation of vibration and noise of a speed increaser, which consist of a star type planetary gears and a planetary type epicyclic gear train. The ring mode vibration of internal gear in the star type planetary gears and torsional vibration of planetary gear in the planetary type epicyclic gear train are measured by use of telemetry system. The influence of tooth profile error for the vibration and the noise is clarified. The numerical simulation is also carried out to evaluate the exciting force and it's associated vibration. In this method, the coupled vibration of shaft bending, torsinal and ring mode vibration of the internal gear are taken into account employing modal synthesis method. The simulation results shows a good agreement with the experimental ones. And it is found that the ring mode vibration magnifies the higher order component of gear mating frequency.