▎ 摘　　要

NOVELTY - The manufacturing method involves introducing a supporting substrate in a reactor then preparing a crystalline alumina catalyst having catalytic activity on the supporting substrate to form an insulating substrate. The nano graphenes are grown on the insulating substrate to manufacture a graphene film including a graphene layer of the nano graphenes. Growing of the nano graphenes is accomplished by pyrolyzing carbon source included in a reactive gas to grow the nano graphenes on the insulating substrate. A metal catalyst is not used in growing the nano graphenes. USE - Manufacturing method of graphene film (claimed) used in e.g. electronic device, photo-electronic device. ADVANTAGE - Enables reuse of the substrate since detachment of graphene film from substrate becomes easy and prevents damaging of the substrate without leaving residual graphene on the substrate. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a graphene film.