To provide a bearing support structure for a transmission capable of reducing a difference of thermal expansion between a shaft and a housing of the transmission, in the transmission wherein a plurality of tapered roller bearings are used back to back to support the shaft.

In the transmission 1, the shaft 2 and the housing 3 are formed of materials having different coefficients of linear expansion. For example, the shaft 2 is formed of copper and the housing 3 is formed of aluminum alloy. The two tapered roller bearings 4, 4 are used back to back to support the shaft 2. At least part of the housing 3 positioned between the two tapered roller bearings 4, 4 along the axial direction of the shaft 2 is formed of a first member 6 having the same linear expansion coefficient as that of the shaft 2.