Disclosed is a C/C composite material precursor which gives a C/C composite material by calcination including: carbon fiber, a matrix, and void-forming core which is burnt out or reduces the volume thereof at lower temperatures than temperature of the calcination and forms a void which has openings on the surface of the C/C composite material after calcination. Also disclosed is a method for producing a C/C composite material by calcination of the precursor; and the composite material obtained by the calcination.