Provided is an external control type fan clutch device with improved operation characteristics of an electromagnetic valve for controlling the amount of oil supply to a torque transmission chamber. In the external control type fan clutch device of a type in which an electromagnet fixed to a rotating shaft side is energized, thereby activating a valve member formed of a plate spring and an armature and provided to a drive disk or a sealed housing to externally control opening and closing an oil circulating flow passage (oil supply port), the valve member is structured so that the armature attached to the plate spring of the valve member is divided into a plurality of pieces in the direction from the base end side to the oscillating end side of the plate spring to provide a plurality of bend points of the plate spring.