A transparent display apparatus is provided that is constructed to transmit or block a light of images selectively according to a supply of electric power to a conventional transparent organic light emitting diode. The transparent display apparatus includes a transparent organic light emitting diode having a glass substrate, a transparent anode, a hole transport layer, an emitting layer, an electron transport layer and a transparent cathode. The transparent display apparatus includes an insulating layer stacked on the transparent cathode, and first and second transparent ITOs stacked on the insulating layer to deliver electromotive force onto an entire surface and to transmit or block the light of images according to the on/off state of a power source. The transparent display apparatus also includes an electro chromic layer provided between the first and the second transparent ITOs and including transparent and colorless chemicals. The electro chromic layer forms a color through oxidation-reduction reaction of the chemicals according to the on/off state of the power source to absorb or block the light of images. The transparent display apparatus further includes a substrate stacked on the second transparent ITO.