To provide a surface-treated steel sheet for battery containers excellent in workability while maintaining battery characteristics and liquid leakage resistance, and a manufacturing method thereof. A surface-treated steel sheet for battery containers according to the present invention includes a Ni—Co—Fe-based diffusion alloy plating layer on at least one surface of a base steel sheet, in which the diffusion alloy plating layer is consisted of a Ni—Fe alloy layer and a Ni—Co—Fe alloy layer, which are arranged sequentially from the base steel sheet side, the diffusion alloy plating layer has a Ni coating weight within a range of 3.0 g/m2 or more and less than 8.74 g/m2 and a Co coating weight within a range of 0.26 g/m2 or more and 1.6 g/m2 or less, with a total of the Ni coating weight and the Co coating weight being less than 9.0 g/m2, when a surface of the diffusion alloy plating layer is analyzed by an X-ray photoelectron spectroscopy, Co: 19.5 to 60%, Fe: 0.5 to 30%, and Co+Fe: 20 to 70% in atom % are satisfied, and a thickness of the Ni—Fe alloy layer is within a range of 0.3 to 1.3 μm.