A ventilating fan including a ventilating fan body provided with a motor, a frame having ventilating air outlets, and fan blades, an adapter and an electric element box. The ventilating air outlets include a top air outlet provided on a top face of the frame of the ventilating fan and a side air outlet provided on a side face of the frame of the ventilating fan which are communicated with each other. The adapter is provided with a raised structure adapted to the ventilating air outlet. With this structure, the height of the ventilating fan is reduced while air volume is ensured, so that the ventilating fan is adapted to be mounted onto various ceilings, and the cost can be saved while mounting of the adapter is simplified.