NOVELTY - A flat alkaline primary battery comprises a positive electrode (2) comprising a positive electrode active material (5) containing nickel oxyhydroxide; a negative electrode (3) comprising a negative electrode active material (7) containing zinc or zinc alloy; and an active material stabilizer in the negative electrode containing highly cross-linked polyacrylic acid, non-cross-linked polyacrylic acid, and carboxymethylcellulose.    USE - As a flat alkaline primary battery useful in a device such as an electronic wristwatch.    ADVANTAGE - The flat alkaline primary battery is inexpensive and has excellent battery capacity and capacity retention. Because nickel oxyhydroxide, whose potential is higher than that of manganese dioxide or silver oxide, is used as a positive electrode active material, a battery voltage higher than that of an alkaline manganese battery or a silver oxide battery is achieved. Further, a highly cross-linked polyacrylic acid is used as an active material stabilizer in the negative electrode mixture. Accordingly, even if the battery is stored at high temperatures, decomposition of stabilizers in the negative electrode mixture due to the oxidation effect of nickel oxyhydroxide of the positive electrode is prevented, thus inhibiting passivation of zinc or zinc alloy powder, which is a negative electrode active material, and achieving high capacity retention. Further, a non-cross-linked polyacrylic acid and carboxymethylcellulose are used as active material stabilizers in the negative electrode mixture. Accordingly, the oxidation resistance of negative electrode active material stabilizers can be improved, and also the viscoelasticity of the negative electrode mixture can be optimized. As a result, a battery having excellent capacity retention can be obtained, in which the negative electrode mixture has excellent handle ability. Therefore, the flat alkaline primary battery is durable for long-lasting use in a device such as an electronic wristwatch, in which the final voltage is set relatively high to suit the battery voltage of a silver oxide battery. As a result, the flat alkaline primary battery does not use an expensive material (silver) like a silver oxide primary battery, and thus can be manufactured at low cost without being influenced by the noble metal market. In the flat alkaline primary battery, a highly cross-linked polyacrylic acid is present as an active material stabilizer in the negative electrode mixture. As a result, a battery having excellent capacity, capacity retention, closed circuit voltage characteristics, and leakage resistance can be obtained. In the flat alkaline primary battery, a non-cross-linked polyacrylic acid is present as an active material stabilizer in the negative electrode mixture. As a result, a battery having excellent leakage resistance can be obtained, in which the negative electrode mixture has excellent handle ability. In the flat alkaline primary battery, carboxymethylcellulose (CMC) is present as an active material stabilizer in the negative electrode mixture.    DESCRIPTION OF DRAWING(S) - The figure shows a sectional view of a button-shaped alkaline battery.    Alkaline primary battery (1)    Positive electrode can (2)    Negative electrode can (3)    Ring-shaped gasket (4)    Positive electrode mixture (5)    Separator (6)    Negative electrode mixture (7)