An alkaline storage battery comprising an electrode assembly housed in a vessel, said electrode assembly comprising a positive electrode plate obtained by filling an active material comprising nickel hydroxide as the principal component into a metallic porous body substrate having three-dimensionally continuous space, followed by pressing, and a negative electrode plate which are opposed to each other with a separator placed therebetween, wherein said positive electrode plate used has been prepared by filling the active material into a plurality of the substrates and then placing at least two of the resulting positive electrode plates one upon another and pressing them to give a single positive electrode plate.