To provide a composition for a sealant, which is transparent, can form a thick film, and is excellent in light resistance, and to provide a light-emitting device and a solar cell module using the composition for the sealant.

The composition for the sealant contains an organic silicon compound comprising a silsesquioxane represented by general formula (1): (R¹SiO_1.5)_n and/or a polymer thereof, and a fluorine-containing organic silicon compound comprising a silsesquioxane represented by general formula (2): (R²SiO_1.5)_n and/or a polymer thereof.