Porous silica-carbon composites are obtained by mixing fine particulate carbon dispersed in water by a surfactant, alkali metal silicate aqueous solution, and mineral acid so as to produce co-dispersion in which silica hydrosol, produced by reaction of the alkali metal silicate and the mineral acid, and the fine particulate carbon are uniformly dispersed, and gelling silica hydrosol, contained in the co-dispersion, and making the co-dispersion into porous bodies. The porous silica-carbon composites are prepared so as to have specific surface area from 20 to 1000 m2/g, pore volume from 0.3 to 2.0 ml/g, and average pore diameter from 2 to 100 nm.