To provide a voltage measurement method of a trip-lock terminal block which is capable of safely measuring voltage, not using a screw as a conductive part.

With the voltage measurement method of the trip-lock terminal block consisting of a plug with a metal conductive plate fitted in protrusion from an insulating support body and a main body screwing down two terminal screws for connecting wires to an insulating block body which conducts both screws with the metal conductive plate inserting the plug into the main body and makes them non-conductive by pulling off the plug from the main body, a locus plate part is formed extended from the metal conductive plate at a place where an operation is possible from the front face of the plug, a detection terminal screw is screwed into the locus plate part, and a pressure terminal is screwed and fastened with the detection terminal screw, to measure voltage of the terminal screw part.