A semiconductor device 100 has a power transistor N1 of vertical structure and a temperature detection element 10a configured to detect abnormal heat generation by the power transistor N1. The power transistor N1 includes a first electrode 208 formed on a first main surface side (front surface side) of a semiconductor substrate 200, a second electrode 209 formed on a second main surface side (rear surface side) of the semiconductor substrate 200, and pads 210a-210f positioned unevenly on the first electrode 208. The temperature detection element 10a is formed at a location of the highest heat generation by the power transistor N1, the location (near the pad 210b where it is easiest for current to be concentrated) being specified using the uneven positioning of the pads 210a-210f.