Method and apparatus for diagnosing deterioration of fuel cell

PURPOSE: A method and an apparatus for diagnosing the deterioration of a fuel cell are provided to measure the alternating current impedance of the fuel cell without damaging the power quality. CONSTITUTION: A method for diagnosing the deterioration of a fuel cell comprises eh following steps: controlling the frequency of the current outputted from the cell; measuring the alternating current impedance of the fuel cell using a pulse component from an output current; and determining the deterioration state of the cell based on the alternating current impedance.