Fuel injector

A magneto-striction element (7) is inserted and held by an element holder assembly (6). A flange (13) at the upper end of the element holder assembly (6) is positioned on a main unit case (1) of the fuel injection valve (6) as a fixed end and the lower end of the element holder assembly (6) is set as a free end which can expand and contract vertically. An inward opening specification is used that when the magneto-striction element (7) expands, the plunger (13) is pulled upward in the injection valve in the opposite direction of the combustion chamber side and from the gap between a nozzle sheet (3) arranged on the combustion chamber side and the front end of the plunger (13), fuel is injected.