Abstract: A carbon fiber composite material (50) includes an elastomer, and carbon nanofibers dispersed in the elastomer in an amount of 0.01 to 0.70 parts by mass based on 100 parts by mass of the elastomer, the carbon nanofibers having an average diameter of 0.4 to 7.0 nm. A method of producing a carbon fiber composite material includes mixing carbon nanofibers having an average diameter of 0.4 to 7.0 nm into an elastomer in an amount of 0.01 to 0.70 parts by mass based on 100 parts by mass of the elastomer, and tight-milling the mixture at 0 to 50° C. using an open roll at a roll distance of 0.5 mm or less to obtain a carbon fiber composite material (50).