Provided is a space-saving soldering device that can perform allowing high-reliability soldering at a low cost and a high yield be produced at low cost with a high yield. For achieving the above-described objects, the soldering device includes: a first treatment part that sets a component having an electrode; a second treatment part separated by an opening-closing unit, the second treatment part sending the component on to a third treatment part; the third treatment part separated by an opening-closing unit, the third treatment part causing the component to contact an organic fatty-acid-containing solution and move horizontally; a fourth treatment part having a unit for moving the component to a space portion and causing molten solder to adhere to the electrode, and a unit for removing excess molten solder; a fifth treatment part for horizontally moving the component moved downward by the fourth treatment part; a sixth treatment part separated by an opening-closing unit, the sixth treatment part sending the component on to a seventh treatment part; and the seventh treatment part separated by an opening-closing unit, the seventh treatment part taking out the component.