To provide an expanded grid hardly broken by proceeding corrosion.

Several parallel slits are made zigzag a in the proceeding direction of an alloy sheet, a line portion formed by the adjacent slits in the width direction of the alloy sheet is plastic-deformed in convex alternatively in both directions front and back from the alloy sheet face, a plain area formed at a non-slit portion is made a node of the said convex line portion, and a mesh portion is formed by spreading this alloy sheet in the width direction. In a manufacturing method of the grill for a storage battery, the slit are made zigzag passing through the alloy sheet to a pair of rolls opposing rolls layered with a disc cutter including the convex processing portion projected in the same distance from the circumference. It is the manufacturing method of the grill for the storage battery using the disc cutter of which concaves are provided to a thickness direction alternatively to both sides of the disc cutter opposing to the said node in the said convex processing portion, and also the circumference portion of at least a non-convex processing portion on a circumferential face of the cutter is beveled to low for face with each concave.