A soldering process device of the present invention has a vertically extending heatable iron tip (5) of substantially tubular shape, and a solder piece supply section for causing a first solder piece (Wh1) and a second solder piece (Wh2), which are provided with a layer of flux (72) inside a pipe-shaped solder layer, to be supplied in the stated order to the inside of the iron tip from above. Once the solder pieces have been oriented upright so that the second solder piece lies on the first solder piece within the iron tip, the heat of the iron tip is used to melt the first solder piece and the second solder piece, whereby molten solder is supplied downwards. It is thereby possible to achieve more reliable thermal melting of solder pieces oriented upright within the iron tip.