PURPOSE: To easily confirm the power source state of an equipment at a power source supplying side, and to prevent a circuit in each equipment from being damaged when a connector is loaded or unloaded, by providing a power source state display means at the connector loaded/unloaded on an equipment to be power-supplied, in a connection equipment which performs a communication by connecting two equipments, and which performs a power supplying from the two equipments to another equipment.

CONSTITUTION: A connection equipment 13 is equipped with a cable 14 on which a power source line, and a communication line are provided, a connector 15 provided at one end of the cable 14, and connected to a power souce installing equipment 11, and a connector 16 provided at the other end of the cable 14, and connected to an equipment 12 to be power- supplied. At the connector 16, a power source state display means 17 connected to a power source line (a), and a GND line (b), is provided. And when the connector 16 is loaded/unloaded on the equipment 12 to be power-supplied, the display means 17 is confirmed. In other words, when the connector 15 is connected to the power source installing equipment 11, and also when the power source of the power source installing equipment 11 is turned on, the display means 17 is lightened, therefore, the loading/unloading of the connector 16 can be performed after only confirming the state where the display means 17 is not lightened. By the above operation, the loading/unloading of the connector at the on-state time of a power source can be prevented from being performed.