A fan module including a blade mechanism, a switch component, and a fan is provided. The blade mechanism includes a frame having a through hole, a positioning bracket movably connected to the frame, and blades movably connected to the positioning bracket and the frame. The switch component is connected to the positioning bracket and located on an assembly path. The fan is detachably disposed at one side of the through hole, and the positioning bracket and the blades are located at another side. In a first mode, any two adjacent blades are stacked to close the through hole. In a second mode, the fan pushes the switch component to drive the positioning bracket to drive the blades, such that the blades have a rotational degree of freedom relative to the positioning bracket or rotate relative to the frame to open the through hole. An electronic device is also provided.