To provide a switching power supply device capable of inhibiting a phase shift in an output.

This switching power supply device having a switching element 2 and an inductor 4 connected to the switching element 2 controls an output voltage by driving the switching element 2 at every switching period. Further, the switching power supply device includes: a current detection unit 5 for detecting inductor current flowing in the inductor 4; a sample-and-hold circuit 15 for sampling the detection result of the current detection unit 5; an error amplifier 8 for amplifying an error between the output voltage and a predetermined reference voltage; and a driving circuit 13 for generating the driving signal of the switching element 2 based on the result obtained by comparing the superimposed result gained by superimposing the amplified result of the error amplifier 8 on a ramp signal with the detection result of the sample-and-hold circuit 15 which is retained by a delay circuit 16 before a predetermined number of switching periods.