A switching regulator is disclosed that includes a switching transistor controlling output of an input voltage by switching in accordance with an input control signal; a smoothing circuit part configured to smooth the output voltage of the switching transistor and output the smoothed voltage to an output terminal; a control circuit part configured to control the switching of the switching transistor in synchronization with an externally input clock signal so that a voltage at the output terminal is a predetermined constant voltage; and a clock signal detector circuit part configured to detect the presence or absence of inputting of the clock signal. Upon detecting stoppage of the inputting of the clock signal, the clock signal detector circuit part causes the control circuit part to stop operating and perform a standby operation for reducing power consumption and thereby to turn off the switching transistor.