A method for growing carbon nanoflakes includes inducing partial etching of graphene layers of carbon nanotubes through an adequate composition of precursor gases, CH4, H2 and Ar, while allowing carbon nanoflakes to grow at the etched site in a plane-like shape. A carbon nanoflake structure is formed by the same method. The method for growing carbon nanoflakes includes: providing a silicon substrate having carbon nanotubes; and growing carbon nanoflakes on the carbon nanotubes through a chemical vapor deposition process using a mixed gas of CH4, H2 and Ar as a precursor. During the chemical vapor deposition process, the mixed gas of CH4, H2 and Ar is in an atmosphere with excess Ar, graphene layers forming the carbon nanotubes are etched partially under the atmosphere with excess Ar, and graphene layers of carbon nanoflakes are grown at the etched site.