A multi-phase switching regulator and a switching regulating method using the multi-phase switching regulator employ an interleaving circuit. The multi-phase switching regulator includes: a first regulating circuit configured to receive an input voltage and generate a first sub-output voltage with a first phase by transforming the input voltage in response to a first set signal; a second regulating circuit configured to receive the input voltage and generate a second sub-output voltage with a second phase by transforming the input voltage in response to a second set signal; and the interleaving circuit configured to repeatedly and sequentially generate the first set signal and the second set signal by comparing a reference voltage with an output voltage generated based on the first sub-output voltage and the second sub-output voltage.