The present invention provides to a circuit interrupting device, particularly a ground fault circuit interrupter (GFCI), with a test circuit which is capable of automatically generating a simulated leakage current to detect whether the service life of the circuit interrupting device has ended, i.e., whether the main components of the device are working properly, when the device is properly connected to power input terminals and in a tripped state. The test circuit contains an end-of-service-life integrated circuit chip, which is connected to a switch that interacts with the reset button, thereby, by observing whether the device is capable of resetting, a user can determine whether the service life of the device has ended, i.e., if the device can be reset, the device is working properly; if the device cannot be reset, the service life of the device has ended. Optionally, the circuit interrupting device contains an indicating light on the face of the device, thereby, by observing whether a normal status indicating light or a problem status indicating light is turned on and displayed on the face of the device, the user can determine whether the service life of the device has ended. The circuit interrupting device also possesses a forcible tripping mechanism through the operation of the test button to interrupt the power output to the device. The present invention also provides methods for detecting the end of service life of the circuit interrupting device.