A sterilization device includes: a frame having a first surface into which air flows, and a second surface from which air flows out; one or more discharge electrodes disposed in the frame; and a plurality of ground electrodes alternately arranged with the discharge electrodes. The discharge electrodes each comprise: a framework extending in the direction parallel to the ground electrodes; a first discharge needle protruding toward the first surface from the framework; and a second discharge needle protruding toward the second surface from the framework. The discharge electrodes are inclined at a predetermined angle with respect to an arbitrary axis of rotation parallel to the direction in which the ground electrodes extend, such that a discharge treatment region is formed perpendicularly to a flow direction by means of the alternate arrangement of the discharge electrodes and the ground electrodes parallel to the flow direction.