To prevent the generation of bruises and scratches or the like when a wire rod in coil is transferred between processing units as well as to encourage labor-saving and improve the efficiency.

The loose wire rod in coil 16, which is rolled with a rolling means 12 and taken up in coil, is delivered with the transfer equipment 22 to a pallet 20 standing at the carrying-out station 18. A carriage 46 on which the pallet 20 of the carrying-out station 18 is transferred is moved with a tractor to the carrying-in station 28 of a heat-treatment unit 24. When the carriage 46 arrives at the carrying-in station 28, the pallet 20 is located on the roller table of the carrying-in station 28. The transfer equipment 22 receives the wire rod in coil 16 on the pallet 20, which is then heat-treated with a heat treatment means 36. The heat-treated wire rod in coil 16 is delivered to the pallet 20 of the carrying-out station 32 with the transfer equipment 22.