A switching circuit device provided between a first node and a second node within a power supply circuit, an
inductor being coupled to the first or second node, the switching circuit device has: a first
transistor that is provided between the first node and the second node and has a first gate width,a second
transistor that is provided in parallel with the first
transistor between the first node and the second node and has a second gate width larger than the first gate width,and a driving
signal generation circuit, which, in response to a
control signal generated according to an output
voltage of the power supply circuit, outputs a first driving
signal which drives the first transistor on and off, and a second driving
signal which drives the second transistor on and off, with different timings between the first driving signal output and the second driving signal output.