The paper presents the results of experimental studies on the implementation of electric arc synthesis of boron carbide using carbon with different morphology and origin as a feedstock: carbon fibers, flake graphite, carbon obtained by pyrolysis of plant waste, namely, pine sawdust and cedar nuts husks. A feature of the electric arc method used is its implementation using an original plasma reactor using atmospheric air as a working gas medium. Oxidation of feedstock and synthesis products in the working cycle of the reactor is prevented due to the generation of CO and CO2 gases in the reaction zone. The possibility of obtaining a material containing micron and submicron boron carbide crystals in a graphite matrix has been experimentally shown. Also, the paper presents information about the features of the oxidation processes of the obtained materials in comparison with commercial samples of boron carbide.