To provide a bearing device of a main motor for a vehicle in which dust or rain hardly enters a labyrinth in the vicinity of a bearing.

The bearing, device comprises a bearing 4b which is provided on a center part of a lid 6 provided on an end part of a cylindrical frame to accommodate a stator and rotatably holds a shaft 7 of a rotor, and a collar 17b which is fitted to the shaft 7 and forms a labyrinth 14b with a predetermined gap G between the lid 6 or an end lid 16 fitted to the lid 6 to press an end face of the bearing 4b, and an opening part H of the labyrinth 14b is formed in the direction of the lid 6.