To provide a thermosetting composition with which a protective layer, producing no disconnection of an ITO, being excellent in high stability in the lapse of time, further scarcely producing a residue on a deep portion in the case a protective film is wiped away and so on, and being excellent in an adhesion property with a sealing material, is formed.

The thermosetting composition for the protective film contains an ethylenically unsaturated compound and/or a compound with an epoxy group in the molecule as a thermal cross-linking agent. In the case 0.1 g of the thermosetting composition is dropped on the center of a 10 cm×10 cm glass substrate, and subsequently is applied thereto with spin coating so as to make dry film thickness of the center portion of the glass substrate 2 μm or more, and in the case a taper angle formed with a side face of the applied layer end portion and the substrate surface is represented by (W1) and a taper angle formed with the side face of the same applied layer end portion and the substrate surface after the applied layer has further been subjected to heat treatment at 230°C for 30 minutes is represented by (W2), a following inequality W1/W2≥1.2 is satisfied.