A pulley fixing structure includes a pulley with a ball bearing, and a bracket having a shaft portion on which the inner race of the bearing is pressed with an interference fit. The thermal expansion of the radially outer portion of the shaft portion of the bracket is larger than that of the radially inner portion of the inner race of the bearing. The interference thus decreases at a low temperature. Reduction of the radial clearance of the bearing 1 by pressing is thus compensated, and cold weather noise can be prevented while reducing the number of required parts and making the assembly process simple.