Abstract: A surface hydrophobic active carbon is disclosed which has undergone a treatment with trimethyl chlorosilane and exhibits a silicon concentration on the surface thereof, Si.sub.2p /C.sub.1s, in the range of 0.005-0.03 as determined by X-ray photoelectron spectroscopy and a humidity for starting adsorption of water in the range of 45-60% as determined from the equilibrium adsorbed water content curve, and a method for the production of a surface hydrophobic active carbon is disclosed which comprises exposing active carbon to trimethyl chlorosilane, allowing the exposure to continue for a prescribed length of time, evacuating the ambience, thereby removing excess amount of trimethyl chlorosilane, and subsequently heating the active carbon under a vacuum.