To provide an automatic vacuum cleaner with a power cord with small restriction by the power cord.

The automatic vacuum cleaner comprises a cleaning unit (not shown) running by itself while changing the direction of running when touches or comes close to an obstacle, and a control unit 2 connected to the cleaning unit by a cord 3 for feeding the electric power to the cleaning unit and transmitting/receiving control signals with the cleaning unit. The control unit 2 comprises a cord reel 22 for taking up the cord 3 with the tension smaller than the self-running power, a distance detecting means 24 for detecting the distance between the cleaning unit and the control unit based on the quantity of take-up of the cord reel 22, and a means for detecting the azimuth of the cleaning unit based on the angle between the cord 3 and a prescribed region of the control unit 2. The control unit 2 controls the running of the cleaning unit based on the distance and the azimuth.