Method of manufacturing a soldering method and an electronic device

PROBLEM TO BE SOLVED: To perform a soldering operation using no flux even when solder material, having a large Sn content, is used while generation of residue is being prevented. SOLUTION: An oxide film removing composition 3 is applied to the surface of solder material 4, the connection pattern 2 of the substrate 1 to be wired and an electronic component 5, provided with the solder material 4, are tacked through the oxide film removing composition 3, and the entirety of the above- mentioned material is heated up and soldered in this soldering method. An organic compound, having an oxide film removing function and containing an oxide film removing agent and a diluting agent, is used as the above- mentioned oxide film removing composition 3.