A plug with a cable includes a plug and a cable. The plug is connected to a receptacle to which a secondary cell is connected. The plug includes a housing and a substrate therein. The cable includes a power supply line and a grounding line. The cable has one end connected to the plug and the other end connected to a power supply unit. A switch is mounted on the substrate and provided in series in a power supply interconnection connected to the power supply line. A temperature sensor is mounted on the substrate and disposed near a power supply terminal or a grounding terminal of the plug. A control circuit is mounted on the substrate and configured to interrupt the power supply interconnection by turning off the switch when a temperature detected by the temperature sensor exceeds a predetermined value.