A joining method that allows joining processing to be carried out simultaneously at a plurality of portions without being influenced by a supply time restriction on a joining material, and a semiconductor device manufacturing method using the joining method are provided. A chip and a lead frame are tentatively assembled having a solid solder block interposed therebetween. The solder block is provided with protruding parts that protrude in one direction. The protruding parts are inserted into solder supply ports of the lead frame, whereby the chip and the lead frame are tentatively assembled. Subsequently, the chip and the lead frame are fed into a reflow oven, and the solder block is melted and thereafter solidified. Thus, the chip and the lead frame are joined to each other.