NOVELTY - The system (10) has a connector (3) that is connected to a power converter device (1) through a cable (2) so as to form an electric power feeding path (5) between the power converter device and a storage battery (41) by mounting a connection port (42) carrying the storage battery of an electric vehicle (4) so that attachment or detachment is possible. An illumination unit (31) is provided in connector to light when the connection port is mounted with the connector so as to illuminate connection port. A control unit (32) controls lighting state of illumination unit.    USE - Power conversion system connected to storage battery mounted in electric vehicle such as plug-in hybrid electric vehicle (PHEV) such as plug-in hybrid car.    ADVANTAGE - The control unit makes the illumination unit to extinguish light in the period whose detection signal of the second detection unit is Low level and starts the electric power supply from the power supply unit to the illumination unit when the detection signal of the second detection unit is set to high level so that the illumination unit is made to light automatically. Thus, special operation for making the illumination unit to light is not required. Since the control unit alerts by changing the luminescent color of the illumination unit, the mismounting of connection port is recognized easily and visually by the user. The illumination unit is positioned in the hole formed in the front surface of the insertion unit where the contact portion is not arranged when the connector has the unused hole so that light is emitted from the front surface facing the advancing direction of the connector at the time of the mounting connection port with the connector. Thus, the connection port is illuminated efficiently with the improved design property of connector and without the deterioration of external appearance.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of the power conversion system. (Drawing includes non-English language text)    Power conversion device (1)    Cable (2)    Connector (3)    Electric vehicle (4)    Electric power feeding path (5)    Power conversion system (10)    Illumination unit (31)    Control unit (32)    Storage battery (41)    Connection port (42)