A carbonaceous particle is provided which comprises a hexagonal flake formed of an aggregate of a plurality of nanocarbons and having a side length of 0.1 to 100 mm and a thickness of 10 nm to 1 mm. Thereby, a carbonaceous particle is provided which has an excellent electron emission performance, has a high electron conductivity, shows excellent characteristics particularly when used for a secondary battery, and can suitably be applied to various devices other than a secondary battery as well.