In a soldering method for soldering an electronic component including a palladium or palladium alloy layer formed on a surface of the electronic component and also including a soldering lead terminal onto a printed wiring board including a soldering land and plated through hole, a solder layer containing tin and zinc as main components is formed on the surfaces of the land through hole by a HAL treatment. The lead terminal is inserted and mounted in the through hole. The printed wiring board is brought into contact with jet flows of a solder containing tin and zinc as the main components to thereby supply a solder to the land and through hole.