POWER TRANSMISSION DEVICE

[Problem] To increase the amount of lubricating oil introduced to a predetermined location. [0002] [Solution] A power transmission device has a pinion gear having a large pinion gear and a small pinion gear, a carrier that supports the pinion gear, a ring gear that meshes with the small pinion gear, an oil supply section positioned above a horizon passing through the center of revolution of the pinion gear, and a downstream-side wall section facing the gear surface of the large pinion gear, the downstream-side wall section being disposed so as to be adjacent to the oil supply section, downstream from the oil supply section in the direction of revolution of the pinion gear when viewed from the axial direction.