Disclosed are an electrode material for a non-aqueous solvent secondary battery, which comprises a composite carbonaceous material in which to the surface of a graphite carbonaceous material is attached a carbonized material of an organic substance in an amount to give a carbon residue of 12 parts by weight or less and 0.1 part by weight or more based on 100 parts by weight of the graphite carbonaceous material, and a process for preparing an electrode material for a non-aqueous solvent secondary battery, which comprises the steps of introducing a slurry obtained by adding an aromatic organic solvent to a mixture of graphite carbonaceous material particles and an organic substance and adjusting viscosity to 10000 cp or lower into a mixing and stirring apparatus having a reaction room which has a paddle rotatable by a shaft in an inner portion thereof, the inner wall surface of the reaction room being formed substantially along the outermost line of rotation of the paddle and also, being provided a mechanism of deaerating a solvent, heating it to a temperature of the boiling point of the solvent or higher and lower than 600 .degree.C while stirring to prepare a solid intermediate and heating said intermediate to 600 .degree.C or higher under inert gas atmosphere to effect carbonization. According to the non-aqueous solvent secondary battery electrode material of the present invention, there can be provided a non-aqueous solvent secondary battery in which good electric characteristics that while maintaining discharging capacity which is as high as graphite, irreversible capacity can be suppressed to extremely low and charging efficiency is excellent can be obtained and further stability to an electrolyte is improved. Also, according to the preparation process of the present invention, a composite carbonaceous material having such high characteristics and uniform characteristics can be prepared stably with good efficiency.