PURPOSE:To form such an enclosed type alkali manganese battery that is excellent in a pressure-proof characteristic and economical, by adding the specified quantity of silver to manganese dioxide or a main active material. CONSTITUTION:In this battery, silver is added to a 100pts.wt. of manganese dioxide or a positive active material in a range between 5 and 20pts.wt. With the silver in quantity in this range added to the manganese dioxide or this main positive active material, an excellent charging characteristic of silver, among others, an excellent pressure-proof characteristic controls a battery system, while galvanic voltage suddenly goes up to the extent of voltage for a pressure proof test, and a charging current flowing in a battery suddenly decreases. Therefore, the galvanic voltage gradually goes up to the extent of voltage for the pressure proof test as a battery whose positive electrode is constituted of the manganese dioxide alone, and it is reached up to the pressure proof voltage for long hours, thus during this while, an electric current continues to flow in the battery. With this continuation, as a result, such as possibility that gas generation becomes much enough is brought to nothing, thus such an enclosed type alkali manganese secondary battery that is excellent in a pressure proof characteristic is produced.