A heating and ventilating fan including a frame, a motor with fan blades, a casing, a heating device, and an air path switching plate disposed at an air outlet of the casing for switching outlets of the ventilating fan and a timing motor. The timing motor and the air path switching plate are fixed on either side of a frame wall. The air path switching plate is connected to the timing motor shaft through a connection part, and controls the air path switching plate to rotate by a constant angle in a single direction. A spring having a first end fixed to the frame wall, and a second end rotating synchronously with the air path switching plate controls the air path switching plate to rotate in an opposite direction to the single direction. When the timing motor is switched off, the spring returns the air path switching plate to its rest position.