A fan coupling device 1 connecting an internal combustion engine 31 to a cooling fan 21 comprises an input shaft 3 driven to rotate by the engine 31, a fluid coupling 12 that transmits torque from the input shaft 3 to the cooling fan 21 via a fluid, and a solenoid valve 13 having a valve main body 18 that adjusts a fluid amount in the fluid coupling 12. A determination as to whether or not the valve main body 18 is stuck in a lifted position on the basis of a rotation speed of the cooling fan 21, is started after the elapse of a predetermined time following output of a signal for returning the valve main body 18 to a closed position, The sticking determination can be performed with a high degree of precision without being affected by variation in the rotation speed of the input shaft 3.