Provided is a surface-treated steel sheet for battery containers (100) that is obtained in such a manner that after iron-nickel alloy plating is performed on a steel sheet (10), a thermal treatment is performed and is characterized in that an outermost layer is an iron-nickel alloy layer (20), and the iron-nickel alloy layer (20) has an average crystal size of 1 to 8 μm at the outermost surface thereof. The present invention makes it possible to provide the surface-treated steel sheet for battery containers that can suppress the elution of iron inside the battery when being used for a battery container, whereby the service life of the battery can be extended and battery characteristics such as discharge characteristics is improved, and to provide a battery container and a battery that can be obtained using the surface-treated steel sheet for battery containers.