PURPOSE: To control automatically the tension applied to the chain of a chain conveyer device simply and easily and also miniaturize the chain conveyer device itself.

CONSTITUTION: The device in the title is bacically composed of a head pulley 1 provided with a head pulley drive device 4, a tail pulley 2 arranged facingly to the head pulley 1 and supported with the space between the head pulley 1 and the tail pulled adjustably, chains wound between the head pulley 1 and the tail pulley 2 and a tension control device 5 for pulling and moving the tail pulley 2 in the right angle direction to its axis by a posture parallel with the head pulley 1 and always giving a tension with a bigness set in advance to the chain in a running.