Window cleaning apparatus capable of supplying power in real-time from inner unit to outer unit

A window cleaning apparatus in which a pair of cleaning units respectively attached to both surfaces of a window by means of a magnetic attraction clean one surface or both surfaces of the window simultaneously while moving along the surface of the window, the apparatus comprising:

• a first cleaning unit disposed on one side of a window and having at least one built-in first magnetic module comprising a magnet;
• and
• a second cleaning unit disposed on the other side of the window so as to be opposed to the first cleaning unit, and having at least one built-in second magnetic module comprising a magnet having an opposite polarity to that of the first magnetic module of the first cleaning unit so as to generate a magnetic attraction between the first magnetic module and the second magnetic module,
• wherein the second cleaning unit comprises an induction electricity generating module for generating an induced electromotive force to produce electricity by using a change in the magnetic field generated from the first magnetic module and/or the second magnetic module.