Disclosed are a power interruption method and a power interruption device based on power phase measurement and arc detection and a method thereof and disclosed are a power interruption method and a power interruption device which accurately determine, when a value measured by a current transformer (CT), a voltage detector, etc., is input into the main control unit, whether the measured value is a value equal to or more than a predetermined threshold through a comparison between phases of voltage and current to effectively prepare for a disaster such as preventing fire or protecting a subsequent circuit by a rapid and accurate power interruption by arc at a load side.