A semiconductor device of an aspect of the present invention comprises a package substrate, one first power supply terminal provided on the package substrate, one second power supply terminal provided on the package substrate, a semiconductor chip disposed on the package substrate, first and second internal power supply circuits provided in the semiconductor chip, one first ESD protection element which is provided in the first internal power supply circuit and which is connected to the first power supply terminal, and a plurality of second ESD protection elements, the second ESD protection elements being provided in the second internal power supply circuit, the size of one second ESD protection element being smaller than that of the first ESD protection element, the second ESD protection elements being connected to the common second power supply terminal.