There are provided an analog-to-digital signal conversion method and apparatus therefor, and a digital phase locked loop circuit including the same. The analog-to-digital signal conversion method may include: generating a first digital output signal having N number of bits by comparing each of N number of delay signals detected from output terminals of N number of delay cells with a reference signal; generating a second digital output signal by comparing an auxiliary delay signal generated by an (N+1)th delay cell with the reference signal; and determining a change in a delay time of each of the N number of delay cells based on the first digital output signal and the second digital output signal.