A shaft device has a shaft (1) and a rolling bearing (3) for rotatably supporting the shaft (1). The shaft (1) is hollow, and a heterogeneous member (25) formed from a material different from that of the shaft (1) is provided in a hollow section (24) of the shaft (1). This reduces frictional resistance at a bearing to reduce torque and suppresses vibration and noise involved in the use of the bearing.
