A wiring board on which an electronic component is to be mounted includes a resist having an opening exposing a joint face which is part of the surface of a wiring layer and to which a terminal of the electronic component is to be joined. In the placing step, the electronic component is placed on the wiring board such that the terminal covers the opening entirely and contacts the solder paste applied onto the joint face. Next, the solder paste applied onto the joint face is heated to melt solder and soften thermosetting resin. This allows the solder to gather in a first space within the opening closed with the wiring layer and the electronic component, while allowing the thermosetting resin to gather in a second space formed between a top side of the resist and a lateral side of the electronic component.