A semiconductor device, comprising: a power transistor with a vertical structure; and a temperature sensing element configured to detect abnormal heat generation in the power transistor, wherein the power transistor includes: a first electrode formed on a first-principal-face side of a semiconductor substrate; and a second electrode formed on a second-principal-face side of the semiconductor substrate; and characterized in that the power transistor further includes: at least one pad (210a-210f, 210g) arranged in a lopsided manner on the first electrode such that an area of said first electrode in the vicinity of one of the at least one pad in which current flowing between the first electrode and the second electrode tends to concentrate most is uniquely identifiable, the at least one pad being in electrical contact with the first electrode, and the temperature sensing element is formed in the semiconductor substrate at a position corresponding to the area in which current flowing between the first electrode and the second electrode tends to concentrate most as identified by the lopsided arrangement of the 2. at least one pad (210a-210f, 210g). a power transistor with a vertical structure; and a temperature sensing element configured to detect abnormal heat generation in the power transistor, wherein the power transistor includes: a first electrode formed on a first-principal-face side of a semiconductor substrate; and a second electrode formed on a second-principal-face side of the semiconductor substrate; and characterized in that the power transistor further includes: at least one pad (210a-210f, 210g) arranged in a lopsided manner on the first electrode such that an area of said first electrode in the vicinity of one of the at least one pad in which current flowing between the first electrode and the second electrode tends to concentrate most is uniquely identifiable, the at least one pad being in electrical contact with the first electrode, and the temperature sensing element is formed in the semiconductor substrate at a position corresponding to the area in which current flowing between the first electrode and the second electrode tends to concentrate most as identified by the lopsided arrangement of the 2. at least one pad (210a-210f, 210g). a first electrode formed on a first-principal-face side of a semiconductor substrate; and a second electrode formed on a second-principal-face side of the semiconductor substrate; and characterized in that the power transistor further includes: at least one pad (210a-210f, 210g) arranged in a lopsided manner on the first electrode such that an area of said first electrode in the vicinity of one of the at least one pad in which current flowing between the first electrode and the second electrode tends to concentrate most is uniquely identifiable, the at least one pad being in electrical contact with the first electrode, and the temperature sensing element is formed in the semiconductor substrate at a position corresponding to the area in which current flowing between the first electrode and the second electrode tends to concentrate most as identified by the lopsided arrangement of the 2. at least one pad (210a-210f, 210g). at least one pad (210a-210f, 210g) arranged in a lopsided manner on the first electrode such that an area of said first electrode in the vicinity of one of the at least one pad in which current flowing between the first electrode and the second electrode tends to concentrate most is uniquely identifiable, the at least one pad being in electrical contact with the first electrode, and the temperature sensing element is formed in the semiconductor substrate at a position corresponding to the area in which current flowing between the first electrode and the second electrode tends to concentrate most as identified by the lopsided arrangement of the 2. at least one pad (210a-210f, 210g).