The invention is a curable composition comprising the following component (A) and component (B):
Component (A): a curable polysilsesquioxane compound having a repeating unit represented by the following specific formula (a-1):
R1—D—SiO3/2 (a-1)
Component (B): a silane coupling agent having a nitrogen atom in its molecule, and
a method for producing the curable composition, and
a cured product obtained by curing the curable composition, and
a method for using the curable composition as an adhesive for an optical element-fixing material, and
a method for using the curable composition as a sealant for an optical element-fixing material, and
an optical device obtained by using the curable composition as an adhesive or a sealant for an optical element-fixing material.
One aspect of the curable composition according to one embodiment of the invention can provide a cured product excellent in adhesiveness and heat resistance and having a low refractive index.