A semiconductor device includes an input terminal, a first aging device whose source is connected to the input terminal to turn on at .tau.1 and turn off at .tau.2 (>.tau.1), a second aging device whose source is connected to the input terminal, whose gate is connected to the drain of the first aging device, and whose drain is connected to the gate of the first aging device to turn on at .tau.3 and turn off at .tau.4 (>.tau.3), a first switch whose one terminal is connected to the drain of the first aging device to turn off when the second aging device is on, a second switch whose one terminal is connected to the drain of the second aging device to turn off when the first aging device is on, and an output terminal connected to the other terminals of the first and second switch elements.