A fan is disclosed. The fan includes a fan frame and a plug. The fan frame includes a circumference portion, an accommodating portion located in the circumference portion and having two sidewalls, and at least two fixed holes respectively disposed on two sidewalls of the accommodating portion. The plug disposed in the accommodating portion of the fan frame includes a base, a bipolar knife-shaped terminal and a cover. The base includes two sides and two connecting portions respectively disposed on the sides to connect the fan frame. The bipolar knife-shaped terminal is disposed on the base and located between the connecting portions of the base. The cover is engaged to the base.