Abstract: A vacuum cleaner has a blower motor; a dust detector responsive to a sucked dust particle due to rotation of the blower motor for producing a dust detecting signal when each of the dust particles is detected passing a portion in a suction passage; counter responsive to the dust detection signal for counting the number of the dust interception particles for a given interval; and input power controller responsive to an output signal of the counter for controlling the input power of the blower motor by selecting an input power value from plural preset input power values in accordance with the number. Controlling input power may be performed in accordance with a pulse width indicative of the dust particle size or the counted number may be modified by pulse width. Another embodiment of the vacuum cleaner has plural light emitting diodes for indicating the number counted to show an operator uncleanliness of the floor.