(EN) The present invention relates to a system for diagnosing an insulating element in a BMS which obtains a battery pack diagnostic signal being output by means of a battery monitoring circuit and passing an insulating element from an input terminal and output terminal of the insulating element and then diagnoses for abnormalities in the insulating element on the basis of a bit arithmetic operation of the obtained battery pack diagnostic signal or which obtains a communication signal being transmitted and received from the input terminal and the output terminal of the insulating element and then diagnoses for abnormalities in the insulating element on the basis of a bit arithmetic operation of the obtained communication signal for transmission and reception.