In a lead-acid battery including an electrode plate group housed in a cell chamber 6 with an electrolyte, each positive electrode plate includes a positive electrode grid made of lead or a lead alloy containing no antimony, and a positive electrode active material with which the positive electrode grid is filled. Each negative electrode plate includes a negative electrode grid made of lead or a lead alloy containing no antimony, a surface layer formed on a surface of the negative electrode grid and made of a lead alloy containing antimony, and a negative electrode active material with which the negative electrode grid is filled. A mass ratio MN/MP falls within a range of 0.70 to 1.10, where MP represents the mass of the positive electrode active material per cell chamber, and MN represents the mass of the negative electrode active material per cell chamber.