A molecular sieving carbon characterized by (A) having a structure in which a number of spherical carbonaceous particles having a particle diameter of 0.8 to 120 micrometers overlap and coalesce three-dimensionally at random, (B) in which continuous pathways running three-dimensionally at random exist between a number of the carbonaceous particles, (C) in which a number of the carbonaceous particles have each a number of micropores communicating with the pathways existing between the particles, and (D) having a carbon content of at least 85% by weight. The molecular sieving carbon is useful for obtaining, for example, a nitrogen gas, oxygen gas or gaseous mixture enriched with either the nitrogen gas or the oxygen gas from a gaseous mixture containing the nitrogen gas and oxygen gas.