To enable connection of internal wiring to a plurality of sheet-shaped photovoltaic elements without impairing flexibility.

An auxiliary metallic foil line 33 is placed so that it is in contact with a back electrode layer 15 of photovoltaic elements P1 and P2, respectively, and fixed on the back electrode layer 15 with adhesive tape 32. By folding up the auxiliary metallic foil line 33, a main metallic foil line 34 is inserted into auxiliary metallic foil line 33 and connected, and fixed on the back electrode layer 15 with adhesive tape 35.