In a method in which the inside surface of the negative electrode cup of
an alkaline battery is coated with metal or metal alloy having a higher
hydrogen overpotential than copper, the mask used for coating processing
has the shape in which: when d is the diameter of the negative electrode
cup, t is the plate thickness of the negative electrode cup, A is the
diameter of the mask opening on the negative electrode cup mounting side,
B is the diameter of the mask opening on the negative electrode cup
supplying side, h is the depth of the negative electrode cup, C is the
thickness of mask on negative electrode cup mounting side, and D is a
tapered angle of the mask opening on the negative electrode cup,
2(2t+d)-B>A .gtoreq.0.7d, (A/2)-h.gtoreq.C>0 mm, and
90.degree.>D.gtoreq.45.degree. are satisfied to coat only the inside
surface area except a cuff portion and cuff bottom portion.