A switching regulator includes a power stage circuit and a controller circuit. The controller circuit includes a first amplification circuit, a second amplification circuit, a ramp signal generation circuit, and a comparator. The first amplification circuit generates an amplification signal according to a difference between a low-pass filtered signal and a feedback signal. The second amplification circuit generates an adjustment signal according to a difference between the feedback signal and a fast response signal. The comparator generates a pulse width modulation signal according to a difference between the amplification signal and a ramp signal to generate a switch control signal. The adjustment signal adaptively adjusts the amplification signal or the ramp signal. The low-pass filtered signal is related to a signal generated by filtering out higher frequency part of the reference signal, and the reference signal is related to a dynamic change of a target level of the output voltage.