An accessory device for covering an electronic device, according to various embodiments of the present invention, comprises: a cover part including a front cover for covering at least a part of the front side of the electronic device, a rear cover for covering at least a part of the rear side of the electronic device, and a side part for connecting the front cover and the rear cover; a first component arranged on the front cover; a second component arranged on the inner side of the rear cover; and a printed circuit board electrically connected to the first component and the second component and arranged from the front cover to the rear cover while traversing the side part, wherein at least part of the printed circuit board can include a flexible structure in the folding region of the cover part, corresponding to the movement of the front cover.