PURPOSE: To stable the soldering executing condition by adjusting the width of a jet nozzle hole of an automatic soldering device in compliance with the width of a printed board.

CONSTITUTION: A jet nozzle body 3 through which melted solder is jetted from an upper hole 2 is provided on a solder tank 1 in which the molten solder is contained, the printed board 4 is transferred and passes above the jet nozzle body 3 and the molten solder is stuck to the lower face of the printed board 4'. In this automatic soldering device, a jet stream opening width of the upper hole 2 of the jet nozzle body 3 is freely adjusted in compliance with the width of the printed board 4. Thus, the jet stream width is kept constant to obtain a stable jet stream having less fluctuation of jet pressure and an accurate soldering is carried out.