To prevent a chain conveyor from stopping or dropping in the transporting speed by precluding a work from inclining, rattling, and vibrating when the work is transferred from the first chain conveyor onto the second chain conveyor.

A chain conveyor 101 is structured so that chains 11 in two parallel rows are set over between two sprockets 12 and 13, and at least two sets of such conveyors 101 are parallel installed in the work transporting direction, and thereon 101 each work is placed and transported. In this conveyor device, coaxially with the sprockets 12 and 13, a pulley 16 is installed which has an outside diameter the same as the maximum outside diameter of the locus of the chains 11 set over between the sprockets 12 and 13.