A semiconductor device according to an exemplary aspect of the invention is capable of being selectively switched between an oscillation circuit and a signal input-output circuit, and includes first and second external connecting terminals that are connectable to an oscillation device; an inverting amplifier an input side of which is electrically connected to the first external connecting terminal through a coupling capacitor and an output side of which is electrically connected to the second external connecting terminal; a feedback resistor connected to the input side and the output side of the inverting amplifier; a bias stabilization circuit that stabilizes a bias applied to the coupling capacitor; a first signal input-output portion connected to the first external connecting terminal; and a second signal input-output portion connected to the second external connecting terminal.