An apparatus for generating electrical energy including a first electrode, a second electrode and one or more nanowires, and a method for manufacturing the apparatus for generating electrical energy. The second electrode may have a concave portion and a convex portion. The first electrode and the nanowire are formed of different materials. The nanowire is formed on the first electrode and is positioned between the first electrode and the second electrode. Because the nanowire is formed on the first electrode, the nanowire may be grown vertically and the uniformity and conductivity of the nanowires may be improved. When a stress is applied to the first electrode or the second electrode, the nanowire is deformed and an electric current is generated from the nanowire due to a piezoelectric effect of the nanowire and a Schottky contact between the nanowire and the electrode which makes contact with the nanowire. Accordingly, when the apparatus for generating electrical energy is bent or pressed in part, electrical energy is generated in response to the applied stress.