To obtain the subject resin composition capable of producing a shaped article having a wide variety of forms and structures in an excellent molding cycle without a necessity of molding excessive parts by compounding an optically curable component and a rapidly phase-transitioning resin component.

This optically shaping resin composition contains (A) an optically curable component which can be cured with irradiation of the light (for example, a urethane acrylate-based, ester acrylate-based, epoxy acrylate-based or epoxy-based optically curable resin) and (B) a rapidly phase-transitioning resin component which has such a function that a phase transition from a sol to 'a gel capable of being differentiated from an optically cured portion' is rapidly brought about when some physical change is given. The component B preferably comprises a reversibly and rapidly phase-transitioning resin component (for example, a mixture of a syndiotactic methacrylate polymer and an isotactic methacrylate polymer) which has such a function that a sol-gel phase transition is reversibly and rapidly brought about when some physical change (preferably, a temperature change) is given.