A fan module is disposed in an electrical device. The electrical device has a main board and a casing. The fan module includes a vane module, a fan motor, a circuit board and a fan housing. The vane module has a hub and a plurality of vanes disposed around the edge of the hub. The fan motor is disposed in the hub. The circuit board is used to control the fan motor, so that the vanes rotate related to an axis of the hub for generating an air flow. The fan housing has a main body portion, a protruding portion and a fixing portion, wherein the protruding portion is located in a side of the main body portion, the vane module and the fan motor are disposed in the main body portion and the circuit board is disposed in the protruding portion.