A semiconductor device comprising: a first semiconductor substrate on which a given circuit is formed; a second semiconductor substrate pasted to the first semiconductor substrate ; and through electrodes electrically connecting the first semiconductor substrate and the second semiconductor substrate to each other, wherein each of the through electrodes is formed such that a respective through-hole is opened through a protection diode structure formed in the first semiconductor substrate , an insulating film is deposited on a side wall of the through-hole , and an electrode material is then filled inside the through-hole in which the insulating film is deposited; wherein the respective through electrode is formed such that the through-hole is opened through the protection diode structure including a well region of one of a P type and an N type formed in the first semiconductor substrate and a diffusion layer of the other of the P type and the N type stacked and formed in the well region ; wherein the diffusion layer is in a floating state having a potential that is not fixed; characterized in that the diffusion layer of the other of the P type and the N type stacked and formed in the well region is formed in a recessed portion of a shallow trench isolation ; in that the protection diode structure is formed on a side of the shallow trench isolation facing away from the second semiconductor substrate ; and in that a recessed portion of the shallow trench isolation is provided individually for each of the through electrodes , and in that the diffusion layer is formed between and in contact with the well region and the shallow trench isolation . a first semiconductor substrate on which a given circuit is formed; a second semiconductor substrate pasted to the first semiconductor substrate ; and through electrodes electrically connecting the first semiconductor substrate and the second semiconductor substrate to each other, wherein each of the through electrodes is formed such that a respective through-hole is opened through a protection diode structure formed in the first semiconductor substrate , an insulating film is deposited on a side wall of the through-hole , and an electrode material is then filled inside the through-hole in which the insulating film is deposited; wherein the respective through electrode is formed such that the through-hole is opened through the protection diode structure including a well region of one of a P type and an N type formed in the first semiconductor substrate and a diffusion layer of the other of the P type and the N type stacked and formed in the well region ; wherein the diffusion layer is in a floating state having a potential that is not fixed; characterized in that the diffusion layer of the other of the P type and the N type stacked and formed in the well region is formed in a recessed portion of a shallow trench isolation ; in that the protection diode structure is formed on a side of the shallow trench isolation facing away from the second semiconductor substrate ; and in that a recessed portion of the shallow trench isolation is provided individually for each of the through electrodes , and in that the diffusion layer is formed between and in contact with the well region and the shallow trench isolation . <EOS>