To provide a bearing device of a rotary electric machine for a railway vehicle, wherein an outer ring of a four-point contact ball bearing that receives a thrust load by a helical gear never develops fretting wear due to a shock load and a vibration during operation of a main motor and has sufficient invulnerability.

The bearing device includes a first bearing arranged at the drive device side of a main motor, a second bearing 53 that is arranged at the opposite side of the drive device of the main motor and supports a radial load generated in a driving shaft 21, and a third bearing 52 that is arranged outside and adjacently to the second bearing 53 and supports a thrust load generated in the driving shaft 21. An outer ring of the third bearing 52 is fitted with a bearing housing 51 via a cylindrical body 54. The outer ring of the third bearing 52 and the cylindrical body 54 are tightly fitted. The cylindrical body 54 and the bearing housing 51 are loosely fitted, with the size of a gap in the fitting section between the cylindrical body and the bearing housing is set exceeding a radial gap of the second bearing 53, and a cylindrical locking means is provided in the fitting section between the bearing housing 51 and the cylindrical body 54.