An electronic device comprising: a sensor configured to detect a state of the electronic device indicative of the electronic device being positioned upside down with the main display area facing downward and contacting a surface or not being positioned upside down; a display comprising a main display area arranged on a front area of the electronic device, and a sub display area which extends from the main display area and is formed on a side surface of the electronic device and is divided into a plurality of segments, wherein the display is configured to output a notification of an event in the main display area or in the sub display area according to the state of the electronic device; and a processor configured to: when an event is received, determine a notification type of the received event according to the state of the electronic device detected through the sensor wherein the notification type is determined to be of a first type if the detected state is indicative of the electronic device being positioned upside down, and when the notification type is of the first type, output a notification of the received event in the sub display area, wherein, when the notification type is of the first type, the processor is configured to control an individual segment of the sub display area or a plurality of segments thereof including a combination of at least two segments, corresponding to the received event, to output the notification, and characterized in that the processor is further configured to: when a state switching of the electronic device from a state indicative of the device being positioned upside down to a state indicative of the device not being positioned upside down is detected while the notification of the received event is output in the sub display area, the processor is configured to determine the notification type to be of a second type, switch the area in which the notification is output from the sub display area to the main display area, and output the notification of the received event in the main display area. a sensor configured to detect a state of the electronic device indicative of the electronic device being positioned upside down with the main display area facing downward and contacting a surface or not being positioned upside down; a display comprising a main display area arranged on a front area of the electronic device, and a sub display area which extends from the main display area and is formed on a side surface of the electronic device and is divided into a plurality of segments, wherein the display is configured to output a notification of an event in the main display area or in the sub display area according to the state of the electronic device; and a processor configured to: when an event is received, determine a notification type of the received event according to the state of the electronic device detected through the sensor wherein the notification type is determined to be of a first type if the detected state is indicative of the electronic device being positioned upside down, and when the notification type is of the first type, output a notification of the received event in the sub display area, when an event is received, determine a notification type of the received event according to the state of the electronic device detected through the sensor wherein the notification type is determined to be of a first type if the detected state is indicative of the electronic device being positioned upside down, and when the notification type is of the first type, output a notification of the received event in the sub display area, wherein, when the notification type is of the first type, the processor is configured to control an individual segment of the sub display area or a plurality of segments thereof including a combination of at least two segments, corresponding to the received event, to output the notification, and characterized in that the processor is further configured to: when a state switching of the electronic device from a state indicative of the device being positioned upside down to a state indicative of the device not being positioned upside down is detected while the notification of the received event is output in the sub display area, the processor is configured to determine the notification type to be of a second type, switch the area in which the notification is output from the sub display area to the main display area, and output the notification of the received event in the main display area.