PURPOSE: To improve reliability of a governor, by a method wherein an amount of fuel injected is usually controlled by an electronic type governor, and when the electronic governor fails in operation, it is switched to a mechanical type governor.

CONSTITUTION: The upper end of a guide lever 9 coupled to a shifter 7 pushed by expansion of a centrifugal weight 5 supported by a cam shaft 3 of a fuel injection pump 1 is driven by an electromagnetic actuator 19. Ordinarily, a fuel control rack lever 4 is controlled by the electromagnetic actuator 19 of an electronic type governor. When the electronic type governor fails in operation, the fuel control rack lever 4 is controlled by a mechanical type governor through a guide lever 9 and a floating lever 10. This, even when a trouble such as discharge occurs, permits control of an amount of fuel injected and enables improvement of reliability of a governor.