The influence of fine particles such as coal and coke on the formation of carbon deposits from coal carbonization gas was studied. The carbon deposition rate on the silica specimen greatly increased when these fine particles coexisted with coal carbonization gas at the temperature from 950 to 1250 K. The carbon deposition rate grew with the increase in the concentration of fines. Fine particles surrounded with pyrolytic carbon on the silica specimen were observed by means of polarized light microscopy. The adhesion of these fines to the silica surface took place only when coal carbonization gas was supplied, but no adhesion occurred in a nitrogen atmosphere. It is suggested that tar mist and/or droplets of condensed polymers with high molecular weight form a liquid bridge between fine particles and the surface of the specimen.