Abstract: Provided is a power distribution box distributing commercial electric power supplied from lead-in electric power lines into branch electric power sources and supplying the branch electric power sources to respective loads connected thereto. More particularly, the present invention relates to a power distribution box equipped with a resistive leakage current detector extracting a resistive leakage current simply and accurately from a resultant leakage current and causing leakage current interruption and alarm to be actuated according to the extraction result.