PURPOSE: To easily and efficiently carry active material by initially impregnating a carrier with an active material which has specific physical properties.

CONSTITUTION: Thin layers of an alkali metal are laminated on the surface of the molding of a carrier made of a carbonaceous material whose atomic ratio of hydrogen to carbon is less than 0.15 and whose (002) face has a spacing d002 of more than 3.37, and are heated to temperatures above the melting point of the alkali metal, preferably lithium, so as to initially impregnate the molding of the carrier with the active material made of the alkali metal. The carbonaceous material may contain other atoms, e.g. nitrogen, oxygen, halogen and the like preferably by 7 mole % or less, more preferably 4 mole % or less, most preferably 2 mole % or less. The ratio of hydrogen to carbon is preferably less than 0.10, more preferably 0.05. The spacing d002 of the (002) face is preferably more than 3.38, more preferably 3.39 to 3.75, most preferably 3.45 to 3.70.