To enable the circuit board to be fixed on a predetermined position and to be conveyed to the solder processing portion.Conveying hooks 10 that hold the printed circuit board W1 therebetween, conveying chains 15a, 15b that drive so that the conveying hooks 10 are movable from a heater part 4 to a solder bath 5, first frames 9A that guide the conveying chains 15a, 15b along the heater part 4, second frames 9B that guide the conveying chain 15 along the solder bath 5, and an absorbing member 124 that is provided between each of the first frames 9A and each of the second frames 9B and absorbs an expansion and contraction based on difference of any thermal expansion between the frames 9A, 9B and the conveying chains 15a, 15b are provided. Since the absorbing member 124 absorbs the expansion and contraction based on difference of any thermal expansion between the frames 9A, 9B and the conveying chains 15a, 15b, it is possible to prevent the conveying chains 15a, 15b from being deviated from the frames 9A, 9B. This enables the printed circuit board W1 to be fixed on the predetermined position and to be conveyed to the heater part 4 and the solder bath 5.