A semiconductor device includes a conductive plate having a front surface on which a semiconductor element is mounted and a sealing resin sealing therein at least the front surface of the conductive plate. The conductive plate includes a structure that traps bubbles in a region where flows of the injected sealing resin merge. The conductive plate has a rectangular shape. The sealing resin is injected from a single inlet on a first longitudinal side of the conductive plate. The region where the flows of the sealing resin merge is a region of a corner of a second longitudinal side that across the semiconductor element, opposes the first longitudinal side from which the sealing resin is injected.