Composition for solar cell panel sealing material and solar cell panel using the same

The disclosed composition for a solar cell panel sealing material contains (a) a vinyl ester resin or an unsaturated polyester resin (10-40 mass%), (b) vinyl monomers and/or (meth)acrylate monomers (30-70 mass%), (c) a denaturant (5-40 mass%) (wherein the sum of the mass percentages of the aforementioned components (a) to (c) is 100 mass%), and (d) a UV-curing agent (0.1-15 parts mass per 100 parts mass of the aforementioned components (a) to (c) combined).