The present invention relates to a supported catalyst having a structure in which a metal catalyst is supported on a core-shell structured support. The support includes core particles and shell particles having a smaller particle diameter than the core particles and coated on the core particles to form a shell layer. Due to this structure, the supported catalyst can be used to produce carbon nanostructures that form a novel secondary structure in which ends of the carbon nanostructures are supported on the supported catalyst and form independent branches and the opposite ends grow and are assembled together. The novel structure is expected to find application in various fields, such as energy materials, functional composites, pharmaceuticals, batteries, and semiconductors, because of its characteristic shape.