The present invention relates to a device that allows an output shaft to perform axial motion and automatic locking, in particular, a manual switch-off device for a permanent magnet switch operating mechanism. A large shoe plate and a small shoe plate are fixed onto a base plate. A transmission shaft is rotatably installed onto the large shoe plate and the small shoe plate that are in parallel with each other. An eccentric wheel is fixed onto the transmission shaft between the large shoe plate and the small shoe plate. An output shaft in parallel with the large shoe plate and the small shoe plate is installed onto the base plate. One end of the output shaft is fixed with an end cap. The large shoe plate has an open slot. The eccentric wheel has a spring column fixed thereon, and the spring column connects to one end of a manual switch-off spring through the open slot. The other end of the manual switch-off spring hooks to a spring mount point on the large shoe plate. The device is simple in structure, low in failure rate, and quick in manual switch-off action. With the permanent magnet operating mechanism, it can be used for tens of thousands of times with no malfunction, and thus no maintenance is needed.