The invention aims to provide a means with which it is possible to improve cycle durability in an electrical device such as a lithium-ion secondary cell. There is used, in an electrical device, a negative electrode active material comprising an Si-containing alloy having a composition represented by chemical formula (1): SixSnyMzAlwAa (where M is one or more transition metal elements; A is unavoidable impurities; and x, y, z, w, and a represent mass% values , where y, z, and w are respectively 2 <= y <= 10, 25 <= z <= 35, and 0.3 <= w <= 3, and x and a are remainders). The composition containsSi-containing alloy.