In other words, in the case where the light-emitting panel of the light-emitting device of one embodiment of the present invention is folded so that the adjacent housings are alternately overlapped to each other, a specified housing between the two housings at ends of the plurality of housings can be reversibly modified into a state in which the light-emitting panel is folded so that the housing is located uppermost or a state in which the light-emitting panel is folded so that the housing is located lowermost.
Note that one embodiment of the present invention is not limited to this structure. All display panels may be bent inward and the plurality of housings may be fixed. For example, FIGS. 16A and 16B illustrate an example of the structure in FIG. 3C in which the plurality of housings are fixed so that all the display panels are bent inward. Even in the case of bending all the display panels inward like this or bending all them outward, the light-emitting device can be appropriately fixed because the directions of the magnetic poles of the ferromagnets accord with each other.
Note that in the case where a display device is not used (in the case where an image is not displayed), all the display panels are preferably bent inward and fixed as illustrated in FIGS. 16A and 16B. Accordingly, the display device can be protected from damage because the upper surface of the display device is not exposed. Therefore, even when the light-emitting device is put in a bag or a pocket, it can be put in a compact way. Moreover, in the case inhere the display device is used, display can be made even in a folded state by fixing the display panels as illustrated in FIG. 3C. Note that one embodiment of the present invention is not limited thereto.