PROBLEM TO BE SOLVED: To prevent voltage vibration from being generated in the case where connected DC equipment is a generation source of voltage vibration, when newly connecting the DC equipment to a DC distribution circuit.SOLUTION: A main body 11 comprises positive and negative electrode pieces 12a and 12b to be inserted into a receptacle insertion port of a DC distribution circuit to which DC equipment is connected and in the main body 11, a capacitor 13 is incorporated which is connected in parallel with the DC equipment when the positive and negative electrode pieces 12a and 12b are inserted into the receptacle insertion port. Thus, since the DC equipment and the capacitor are connected in parallel when the positive and negative electrode pieces are inserted into the receptacle insertion port, capacitance of the capacitor becomes high and an oscillation state can be canceled, thereby preventing voltage vibration.
