A semiconductor apparatus includes: first and second power-supply terminals; an internal circuit connected between the first and second power-supply terminals; and a protection circuit connected in parallel with the internal circuit between the first and second power-supply terminals, the protection circuit including: a series circuit that includes a resistor and a first capacitor, and is connected in parallel with the internal circuit between the first and second power-supply terminals; a first MOS transistor that is connected in parallel with the series circuit, and is controlled according to a voltage at a connection point between the resistor and the first capacitor; and a switch circuit that is connected in parallel with the resistor, is turned on in a delayed manner after a power-supply voltage is applied between the first and second power-supply terminals, and changes the voltage at the connection point so that the first MOS transistor is turned off.