Button mechanism and electronic device therewith

A button mechanism includes a circuit structure and an actuating structure. The circuit structure includes a substrate, a first electrode layer, and a second electrode layer. The first electrode layer and the second electrode layer are disposed on the substrate, and the second electrode layer is separated from the first electrode layer. The first electrode layer includes a first section and a second section. The second electrode layer includes a third section and a fourth section. The second section stretches to the third section, and the fourth section stretches to the first section. A predetermined gap is formed between the first electrode layer and the second electrode layer, and the predetermined gap includes a plurality of curved portions. The actuating structure includes a conductive portion for conducting the first electrode layer and the second electrode layer.