A preload torque value generating unit generates a preload torque value as a function of the acceleration of a main motor, the preload torque value being a torque value that is appended in advance to a torque command value so that the direction of force applied to the main motor and the direction of force applied to a sub motor will become opposite to each other. Computation is placed in switch-elements of the computation graph. The recess of the opposing member and the transport roller define a space therebetween to receive the disk inserted from a position deviating from the transport center line in the second direction. The foam arms may be mechanically restrained while being heated. The filter has enhanced strength properties.