A grounding resistance measurement apparatus measures a grounding resistance at an AC power terminal, and is electrically connected to an equipment input terminal which provides an AC power source. The grounding resistance measurement apparatus includes a DC power generation circuit and a DC voltage detection circuit. The DC power generation circuit receives the AC power source at the equipment input terminal and converts the AC power source into a DC power source. The DC power source is provided to produce a DC resistance voltage across the grounding resistance. A voltage difference between the equipment input terminal and an equipment grounding point is equal to the DC resistance voltage so that the grounding resistance is calculated according to the zero DC component in an AC power loop.