A display device comprising: a display configured to display at least a portion of an omnidirectional image; a user input interface configured to input a display mode of the omnidirectional image to be one of a first display mode and a second display mode; and a controller, characterized in that the controller is configured to: in response to the input display mode being the first display mode, set a size of an area of the omnidirectional image to be displayed on the display to correspond with an aspect ratio of the display, in response to the input display mode being the second display mode, set the size of the area of the omnidirectional image to be displayed on the display to correspond with an aspect ratio that is different than the aspect ratio of the display, wherein the second display mode includes: a horizontal display mode for displaying a partial image, the area of the omnidirectional image to be displayed further including an additional area of the omnidirectional image located in a horizontal direction of the area of the omnidirectional image to be displayed according to the first display mode, and a vertical display mode for displaying a partial image, the area of the omnidirectional image to be displayed further including an additional area of the omnidirectional image located in a vertical direction of the area of the omnidirectional image to be displayed according to the first display mode, acquire a first partial image having an area having the set size from the omnidirectional image, and display the acquired first partial image of the omnidirectional image on an entire area of the display. a display configured to display at least a portion of an omnidirectional image; a user input interface configured to input a display mode of the omnidirectional image to be one of a first display mode and a second display mode; and a controller, characterized in that the controller is configured to: in response to the input display mode being the first display mode, set a size of an area of the omnidirectional image to be displayed on the display to correspond with an aspect ratio of the display, in response to the input display mode being the second display mode, set the size of the area of the omnidirectional image to be displayed on the display to correspond with an aspect ratio that is different than the aspect ratio of the display, wherein the second display mode includes: a horizontal display mode for displaying a partial image, the area of the omnidirectional image to be displayed further including an additional area of the omnidirectional image located in a horizontal direction of the area of the omnidirectional image to be displayed according to the first display mode, and a vertical display mode for displaying a partial image, the area of the omnidirectional image to be displayed further including an additional area of the omnidirectional image located in a vertical direction of the area of the omnidirectional image to be displayed according to the first display mode, acquire a first partial image having an area having the set size from the omnidirectional image, and display the acquired first partial image of the omnidirectional image on an entire area of the display. in response to the input display mode being the first display mode, set a size of an area of the omnidirectional image to be displayed on the display to correspond with an aspect ratio of the display, in response to the input display mode being the second display mode, set the size of the area of the omnidirectional image to be displayed on the display to correspond with an aspect ratio that is different than the aspect ratio of the display, wherein the second display mode includes: a horizontal display mode for displaying a partial image, the area of the omnidirectional image to be displayed further including an additional area of the omnidirectional image located in a horizontal direction of the area of the omnidirectional image to be displayed according to the first display mode, and a vertical display mode for displaying a partial image, the area of the omnidirectional image to be displayed further including an additional area of the omnidirectional image located in a vertical direction of the area of the omnidirectional image to be displayed according to the first display mode, a horizontal display mode for displaying a partial image, the area of the omnidirectional image to be displayed further including an additional area of the omnidirectional image located in a horizontal direction of the area of the omnidirectional image to be displayed according to the first display mode, and a vertical display mode for displaying a partial image, the area of the omnidirectional image to be displayed further including an additional area of the omnidirectional image located in a vertical direction of the area of the omnidirectional image to be displayed according to the first display mode, acquire a first partial image having an area having the set size from the omnidirectional image, and display the acquired first partial image of the omnidirectional image on an entire area of the display.