An illumination device includes a transparent substrate and multiple first metal lines. The transparent substrate includes an emitting area and a peripheral area and the emitting area includes multiple sub-emitting areas. The first metal lines are disposed on the transparent substrate, each first metal line has an end connected to a corresponding one of the sub-emitting areas and an opposite end connected to the peripheral area. Each sub-emitting area includes an insulating layer, a second metal line and an OLED layer. The second metal line is disposed between the transparent substrate and the OLED layer, the insulating layer is between the first metal lines and the second metal line, each first metal line is overlapped with the second metal line in vertical projection. One of the first metal lines, which is connected to a first one of the sub-emitting areas, passes through a second one of the sub-emitting areas.