A charging circuit interrupting device for applying an input voltage provided by first and second input power lines of a power system to first and second output power lines of an output system includes a current-detecting unit, a self-test device, and a controller. The current-detecting unit executes a leakage-detection function and generates a leakage signal when the current difference between the first and second power lines is detected. The self-test device generates a bypass path according to the detection enable signal so that there is a current difference between the first and the second input power lines. When operating in a self-test mode, the controller generates the detection enable signal, determines that the leakage-detecting function is normal, and enters a normal mode to apply the input voltage to the output system when the leakage signal is received.