Negative electrode active material for an electric device and an electric device using the same

An object of the present invention to provide means capable of improving the cycle durability of the electrical device such as a lithium-ion secondary battery. The present invention relates to a negative electrode active material for an electric device. Negative active material for the electrical device consists of an amorphous or in the matrix phase mainly composed of low-crystalline silicon, silicon-containing alloy having a structure in which the silicide phase comprising silicides of transition metal is dispersed . Silicon-containing alloy is represented by the following chemical formula (1): In (Formula (1), A is the inevitable impurities, M is one or more transition metal elements, x, y, z, and a represent the value of mass%, this time, 0 silicide phases, to the total number of the silicide phase, has a feature in that at least 2%. .FIELD 3A