A steering controller uses a photointerrupter that detects the position of a filler when a steering roller is in a predetermined reference inclined position. The steering controller drives a steering motor to bring the steering roller to the reference inclined position based on a detection result obtained by the photointerrupter every time predetermined adjustment timing arrives or every time the power is turned on. Using the rotation angle of the steering motor in this condition as a reference rotation angle, the steering controller controls the rotation of the steering motor.