A composite electric circuit breaker, and method thereof, is configured to detect signals regarding arc faults, overcurrent, and earth leakage. Arcs and electric currents are detected by a current transformer and earth leakage is detected by a zero phase current transformer. A variation of electric current, the number of arcs which are generated per a unit time, a present electric current value, and electric current earth leakage are combined to judge whether arc faults occur to then interrupt an electric power supply. Temperature is measured on a printed circuit board, and if temperature rise occurs, the electric power supply is interrupted, and an interruption cause is displayed. Electric accidents and occurrence of fires are prevented simultaneously and more accurately. The interruption causes can be confirmed, analyzed and externally monitored through a network, to thus maximize efficiency of electric management.