1. A display device comprising:a display module;
an outer case in which the display module is mounted and defining an internal space which is closed airtight from the outside;
an inner case coupled to the display module,
wherein the inner case which partitions off the internal space into a first closed space having a rear surface of the display module exposed thereto and a second closed space having a front surface of the display module exposed thereto, and
wherein the first closed space is surrounded by the second closed space with respect to one cross section; and
a first open hole configured to allow a first region of an outer surface of the outer case and a second region of an outer surface of the inner case adjacent to the first region to form an outer passage,
wherein the first open hole passes between the first closed space and the second closed space.