A monitoring circuit includes a sensor circuit having a plurality of devices and a selection circuit, which selects a device to be monitored among the plurality of devices, an input circuit, which applies, based on input digital data, a first signal to the device to be monitored and an output circuit, which generates output digital data based on a second signal generated by the sensor circuit. The input circuit includes a digital-to-analog converter, and the output circuit includes an analog-to-digital converter.