To improve productivity by effectively utilizing an inside area even when a conveyor line is arranged as a round passage by facilitating installation work in a carrying device carrying a work while performing the installation work.

A free flow type conveyor line is provided for mounting the work on a pallet 2 traveling in the substantially same height as a work floor surface in a floor surface of the pallet. A horizontally curved part is arranged in a part of the line, and the pallet 2 is divided into first, second and third divided pallets 2A, 2B and 2C in the carrying direction, and the respective divided pallets 2A, 2B and 2C can mutually freely rotate in a horizontal plane by respectively connecting the first and second divided pallets 2A and 2B and the second and third divided pallets 2B and 2C by a vertically turning pivot pin 9.