There is provided a device and method for detecting an overlap of pulse signals, capable of easily detecting a point where reference and delayed pulse signals overlap each other, and an apparatus for estimating a distance using the same. The device for detecting an overlap of pulse signals, the device detecting a point where first and second pulse signals having different frequencies begin to overlap each other, the device including: a duty adjustor generating a third pulse signal by increasing a duty of the second pulse signal; a pulse signal calculator multiplying the first and second pulse signals by the third pulse signal, respectively and adding respective results together to output a signal; and an overlap determiner determining a middle of a pulse with a greatest width in the signal outputted from the pulse signal calculator as a point where the first and second pulse signals overlap each other.