To provide an automatic fuel supply device capable of preventing falling objects from hitting a switch box.

This device is provided in an oil hydraulic shovel, and has a fuel tank 6; an oil supply pump 10 with an electric motor for supplying fuel oil to the fuel tank 6; an attachment stand 9 of the oil supply pump 10; and a switch box 11, in which a switch for operating the electric motor is built. An accommodation space 9b of the switch box 11 is formed below the attachment stand 9, and the switch box 11 is arranged in the accommodation space 9b. The attachment stand 9 includes an installation part 9a, on which the oil supply pump 10 is installed, and a wall part 9c installed below the putting part 9a and attached to the switch box 11. A case forming an outer shell of the switch box 11 is formed of, for example, synthetic resin, and the switch box 11 is equipped with an operation part 16 operating the built-in switch.