[Object] To provide a nanocarbon/aluminum composite material having high strength and electrical conductivity for suitable use in a lead wire, a heat exchanger and an automotive part and a process for producing the nanocarbon/aluminum composite material. [Solution] There is provided a plating liquid for nanocarbon/aluminum composite production, comprising an aluminum halide, nanocarbon and 1,3-dialkylimidazolium halide and/or the like, wherein the molar ratio of the aluminum halide to the 1,3-dialkylimidazolium halide and/or the like is in the range of 20:80 to 80:20 and the 1,3-dialkylimidazolium halide and/or the like has an alkyl group with a carbon number of 1 to 12. There are also provided a nanocarbon/aluminum composite production process comprising forming a plating film on a substrate surface by electrolysis of the plating liquid in a dry, oxygen-free atmosphere with the passage of a direct current etc. under the electrolysis conditions of a bath temperature of 0 to 300.degree. C. and a current density of 0.01 to 50 A/dm.sup.2 and a nanocarbon/aluminum composite material produced by this production process.