PURPOSE: To shorten a chain pitch and to perform free restoration, by a method wherein, in a chain conveyor having a chain attachment, the coupling shaft of a chain plate having a chain attachment is supported by means of a rail extending in parallel to the conveyor, and the chain attachment is risen and fallen by means of a guide rail.

CONSTITUTION: Under a state (a) in which first and second link plates 4 and 6 are brought into a linear state centering around an axis 5, rollers 8 and 10 are brought into contact with a guide rail 15 and a rail 11, respectively. Since, in a position (b) where the guide rail 8 forms a down slope, the roller 8 is forced down simultaneously with conveyance, the link plates 4 and 6 are bent centering around the axis 5 to shorten a chain pitch. Further, when the link plate 6 is bent to bring it into a vertical state, a pitch is minimized. When the plate is raised, a reverse motion is effected to restore the pitch to its origi nal value. This constitution enables free shortening and restoration of a chain pitch.