Alkaline battery silver oxide powder when soaked in a 50° C. KOH 40% aqueous solution for 24 hours experiences dissolution of Ag into the solution of 40 mg/L. Alkaline battery silver oxide powder exhibits substantially no Ag peak by X-ray diffraction even after soaking in a 50° C. KOH 40% aqueous solution for 72 hours. This powder has a crystallite size calculated from the half value breadth of the (111) plane peak by powder X-ray diffraction of greater than 250 Angstrom and equal to or less than 1000 Angstrom, particle diameter such that the average diameter of secondary particles is equal to or greater than 1 μm and equal to or less than 500 μm and that of primary particles forming the secondary particles is equal to or greater than 0.1 μm and equal to or less than 10.0 μm, and specific surface area of 5 m2/g or less.