Provided is a sheet-like device suitable for a flexible electrical product that is robust, highly flexible, and operates stably. The sheet-like device includes a first part where a first film layer, a first conversion unit, and a second film layer overlap, a second part where the first film layer is absent and the second film layer is present, and a third part where the first film layer, a second conversion unit, and the second film layer overlap. The first part the second part, and the third part are arranged side by side in this order in a first direction. A first region including the first part the second part, and the third part has an elongation per unit length greater than an elongation per unit length of the first film layer alone when a same force is applied in the first direction at 20° C.