The present invention provides a process for producing a composite of metal sulfide and metal oxide obtained by dispersing a metal sulfide, which is nickel sulfide, copper sulfide, iron sulfide or a mixture thereof, in a metal salt-containing aqueous solution, and depositing metal salt on the metal sulfide by drying the aqueous solution; and heat-treating the metal sulfide comprising a metal salt deposited thereon at 400 to 900° C. in a sulfur-containing atmosphere. Also disclosed is a composite obtained by the aforementioned process, comprising a metal sulfide having a surface partially covered with a metal oxide. The composite of the present invention has improved cycle characteristics while maintaining a high charge/discharge capacity and excellent electrical conductivity inherently possessed by metal sulfide, which is usable as a material having a high theoretical capacity and excellent electrical conductivity when used as a positive-electrode material for a lithium secondary battery.