An electronic device comprising: a main body; a display configured to play back a 3D screen corresponding to first virtual reality content; a sensor; a controller configured to, when an event occurs in at least one application while the 3D screen is displayed, output notification information notifying about the event occurrence in correspondence to the 3D screen; the device being characterized in that the controller is further configured to: detect a movement of the main body or a user by using the sensor and a movement of a user through sensors (241, 242) J Z provided in controllers (200A, 200B) that operate in linkage with the electronic device; when a degree of movement of the user or the main body sensed during the event is within or exceeding a critical range, maintain the playback state of the 3D screen; when the degree of movement of the user or the main body sensed during the event is slowed to less than the critical range, stop the playback of the 3D screen and play back dummy content related to the 3D screen, wherein the dummy content is a second virtual reality content related to the playback-stopped 3D screen, and wherein a second virtual object generated by mimicking a virtual object included in the playback-stopped 3D screen is displayed in the second virtual reality content; and remove the dummy content when the event ends. a main body; a display configured to play back a 3D screen corresponding to first virtual reality content; a sensor; a controller configured to, when an event occurs in at least one application while the 3D screen is displayed, output notification information notifying about the event occurrence in correspondence to the 3D screen; the device being characterized in that the controller is further configured to: detect a movement of the main body or a user by using the sensor and a movement of a user through sensors (241, 242) J Z provided in controllers (200A, 200B) that operate in linkage with the electronic device; when a degree of movement of the user or the main body sensed during the event is within or exceeding a critical range, maintain the playback state of the 3D screen; when the degree of movement of the user or the main body sensed during the event is slowed to less than the critical range, stop the playback of the 3D screen and play back dummy content related to the 3D screen, detect a movement of the main body or a user by using the sensor and a movement of a user through sensors (241, 242) J Z provided in controllers (200A, 200B) that operate in linkage with the electronic device; when a degree of movement of the user or the main body sensed during the event is within or exceeding a critical range, maintain the playback state of the 3D screen; when the degree of movement of the user or the main body sensed during the event is slowed to less than the critical range, stop the playback of the 3D screen and play back dummy content related to the 3D screen, wherein the dummy content is a second virtual reality content related to the playback-stopped 3D screen, and wherein a second virtual object generated by mimicking a virtual object included in the playback-stopped 3D screen is displayed in the second virtual reality content; and remove the dummy content when the event ends.