A resin sealing method of a semiconductor device, is provided with: providing a semiconductor device on which a dummy dump is formed; providing a support body including an adhesive layer provided on a surface of the support body; forming a recess in the adhesive layer; inserting the dummy bump of the semiconductor device into the recess of the adhesive layer; adhering the semiconductor device to the adhesive layer with the semiconductor device positioned on the support body; setting the supporting body having the semiconductor device in a resin sealing mold; supplying a resin into a cavity of the resin sealing mold; sealing the semiconductor device with the resin on the support body while using the dummy bump to inhibit displacement of the semiconductor device caused by a flow of the resin supplied into the cavity of the resin sealing mold; and removing the support body, the adhesive layer, and the dummy bump from the semiconductor device sealed with the resin.