To provide a photosensitive composition having low viscosity and excellent heat resistance and mechanical strength.

The photosensitive composition includes 0.01-98 mass% of a polymerizable monomer (A) having one or more functional groups X meeting the following conditions, 0.01-98 mass% of a polymerizable monomer (B) having one or more functional groups Y meeting the following conditions and having no functional group X, and 0.01-15 mass% of a photopolymerization initiator. The conditions are: the functional group X attains a reaction rate of 50% by exposure in a specific exposure condition and a reaction rate of 80% by heat treatment carried out further at 200C for 30 min after the exposure; and the functional group Y attains a reaction rate of 50% by exposure in a specific exposure condition and a reaction rate of 80% by heat treatment carried out further at 200C for 30 min after the exposure.