A bidirectional display device may include: a first transparent display panel outputting a first image in a first direction and transmitting light reflected in a second direction that is an opposite direction of the first direction; a first transparent light panel disposed behind the first transparent display panel and providing light to the first transparent display panel; a transmittance control panel disposed behind the first transparent light panel; a second transparent display panel outputting a second image in the second direction and transmitting light reflected in the first direction; a second transparent light panel disposed between the transmittance control panel and the second transparent display panel and providing light to the second transparent display panel; a transmittance controller and controlling transmittance of at least one object included in the first image or the second image; and an image output controller controlling output of the first image and the second image.