Measuring device for measuring property of fuel inside fuel tank

A measuring device comprising:

• a cover configured to close an opening provided on a fuel tank;
• a plug configured to close a through hole provided on the cover;
• and
• a sensor configured to measure a property of fuel inside the fuel tank,
• wherein
• the plug comprises:
• an electrical connector pierces through the plug from an upper surface to a lower surface of the plug;
• and
• a fuel passage including an inlet configured to open to the inside of the fuel tank to receive the fuel from the inside of the fuel tank,
• one end of the electrical connector on an upper surface side is connected to a control circuit disposed at an outside of the fuel tank,
• another end of the electrical connector on a lower surface side is connected to an electrical equipment disposed in the inside of the fuel tank via a lead wire,
• the electrical equipment is configured to be driven by a power of an external power source,
• the sensor is disposed in the fuel passage of the plug, and
• the fuel passage includes an outlet that is configured to open to the inside of the fuel tank to discharge the fuel from the fuel passage to the inside of the fuel tank.