Provided is a semiconductor device that includes a semiconductor chip, and a packaging substrate on which the semiconductor chip is mounted. The semiconductor chip includes a chip body and a plurality of solder-including electrodes that are provided on an element-formation surface of the chip body. The packaging substrate includes a substrate body, and a plurality of wirings and a solder resist layer that are provided on a front surface of the substrate body. The solder resist layer is provided as a continuous layer on the front surface of the substrate body and the plurality of wirings, and has an aperture on each of the plurality of wirings. The aperture has a planar shape elongated in a lengthwise direction of the wiring inside the aperture, with a length of the aperture adjusted in accordance with a thermal expansion coefficient of the packaging substrate.