An input circuit for a semiconductor integrated circuit in which an operational state is constant even when a process condition, a temperature, a voltage, and the like are varied at the time of operation is provided. The input circuit includes a first input unit that performs a first amplifying operation on a potential difference between a reference voltage and an input signal and outputs a result of the amplification, and a second input unit that performs a second amplifying operation on a signal amplified by the first input unit and outputs a result of the amplification.