A mobile terminal comprising: a terminal body; a transparent display unit having a first transparent substrate configured to sense a touch input and a second transparent substrate configured to sense a touch input, wherein the first and second transparent substrates are stacked on top of each other with an image layer between them; a sensing unit configured to sense at least one of a motion of the terminal body and a rotation of the terminal body, the sensing unit comprising an eye detector configured to sense whether a user is viewing either the first transparent substrate or the second transparent substrate; and a controller configured to: output a content on the first transparent substrate facing with the user; detect an occurrence of an event; display an icon indicating the event generation on the second transparent substrate not facing with the user while the content is displayed on the first transparent substrate facing with the user, the icon displayed on the second transparent substrate being transmitted onto the first transparent substrate at a level which depends on transparency information set for each of the first and second transparent substrates; if the sensing unit senses that the user has switched to viewing the second transparent substrate: display information related to the event on the second transparent substrate; and pause the content being displayed on the first transparent substrate; and if a touch input is applied to a position where the icon is displayed on the second transparent substrate: display information relating to the event on the first transparent substrate facing with the user and simultaneously output the content, which is being output on the first transparent substrate, on the second transparent substrate. a terminal body; a transparent display unit having a first transparent substrate configured to sense a touch input and a second transparent substrate configured to sense a touch input, wherein the first and second transparent substrates are stacked on top of each other with an image layer between them; a sensing unit configured to sense at least one of a motion of the terminal body and a rotation of the terminal body, the sensing unit comprising an eye detector configured to sense whether a user is viewing either the first transparent substrate or the second transparent substrate; and a controller configured to: output a content on the first transparent substrate facing with the user; detect an occurrence of an event; display an icon indicating the event generation on the second transparent substrate not facing with the user while the content is displayed on the first transparent substrate facing with the user, the icon displayed on the second transparent substrate being transmitted onto the first transparent substrate at a level which depends on transparency information set for each of the first and second transparent substrates; if the sensing unit senses that the user has switched to viewing the second transparent substrate: display information related to the event on the second transparent substrate; and pause the content being displayed on the first transparent substrate; and if a touch input is applied to a position where the icon is displayed on the second transparent substrate: display information relating to the event on the first transparent substrate facing with the user and simultaneously output the content, which is being output on the first transparent substrate, on the second transparent substrate. output a content on the first transparent substrate facing with the user; detect an occurrence of an event; display an icon indicating the event generation on the second transparent substrate not facing with the user while the content is displayed on the first transparent substrate facing with the user, the icon displayed on the second transparent substrate being transmitted onto the first transparent substrate at a level which depends on transparency information set for each of the first and second transparent substrates; if the sensing unit senses that the user has switched to viewing the second transparent substrate: display information related to the event on the second transparent substrate; and pause the content being displayed on the first transparent substrate; and display information related to the event on the second transparent substrate; and pause the content being displayed on the first transparent substrate; and if a touch input is applied to a position where the icon is displayed on the second transparent substrate: display information relating to the event on the first transparent substrate facing with the user and simultaneously output the content, which is being output on the first transparent substrate, on the second transparent substrate.