The utility model discloses a wheel base adjusting device for locomotive bed, including many wheel bases adjustment drive mechanism and driving motor, the each shaft sets up separately at locomotive bed's rail wheel platform and transmission platform's both ends apart from adjustment drive mechanism, is arranged in to adjust drive mechanism with the wheel base of delegation's rail wheel platform and transmission platform tip and have at least a wheel base to adjust to be provided with driving motor on the drive mechanism. This a wheel base adjusting device for locomotive bed has labour saving and time saving, convenient accurate, the experimental little advantage in space of taking up an area of of wheel base adjustment.