A duty correction circuit is presented for use in compensating for a duty rate error brought about when a malfunction of a clock signal generator or a failure of a signal transmission line occurs. The duty correction circuit is configured to select one of differential signals as an input signal according to a duty rate. The duty correction circuit is also configured to combine the input signal and a signal obtained by delaying the input signal by a delay time adjusted in accordance to the duty rate. The duty correction circuit is also configured to generate the combined signal as a duty correction signal.