The power transmission apparatus includes: a gear chamber, used for accommodating gears disposed on a rotating shaft used for transmitting power to a drive wheel; a clutch chamber, disposed adjacent to the gear chamber in an axial direction of the rotating shaft, and used for accommodating a clutch used for disconnecting or connecting the power transmitted by the rotating shaft to the drive wheel; and a communicating hole, used for communicating the clutch chamber with the gear chamber, where an inclined surface facing toward the communicating hole is provided on an inner surface inside the clutch chamber opposite to an outer peripheral surface of the clutch.