To provide a manual operating device of a self-traveling truck system capable of detaching a traveling guide of a chain or the like and moving a truck in an emergency.

In an emergency, when a worker pulls an operating member upwardly close to a second end plate, a releasing bracket 19 is moved in a direction indicated by an arrow A in a broken line against the urging force of a spring 23 via a wire part 22b of a coaxial wire 22, and an end 18 of a chain 16 is also moved together with the releasing bracket 19. When the end reaches an open end of a cutout of a first end plate 14, a bolt part at the end 18 of the chain 16 is dropped from the open end of the cutout, and comes off from the first end plate 14.