The invention aims at providing a non-aqueous secondary battery which exhibits a satisfactorily small irreversible capacity in the initial charge and discharge cycle even when the density of a negative electrode active material layer on a current collector is enhanced in order to obtain a higher capacity and the aim can be attained by composite graphite particles for non-aqueous secondary batteries which are obtained by incorporating spherical graphite particles with a binder graphite, the quantity of CO groups present on the surface standardized by BET specific surface area is 1.15 to 5mu mol/m2; the average sphericity is 0.85 to 0.95. Thus, the problem can be solved.