POWER TRANSMISSION DEVICE

[Problem] To reduce stirring resistance.[Solution] This power transmission device comprises: a pinion gear which comprises a large pinion gear and a small pinion gear; a wall which axially overlaps the revolving orbit of the large pinion gear; a plate which is provided between the wall and the large pinion gear; and a bottom part which, with an interposed clearance gap, is disposed below the plate and the revolving orbit of the large pinion gear.