To provide a valve device that is easy to change a design by reducing transfer loss of force by a difference of coefficient of thermal expansion.

When electric energy is supplied to a Piezzoelectric element 51 of a driving component 50. The piezzoelectric element 51 elongates and a 1st piston 52 moves to the direction of an oil pressure chamber 54. Oil pressure of the oil pressure chamber 54 rises associated with the movement of the 1st piston 52, and a 2nd piston 53 drives a valve member 41 through a lever member 60. The displacement magnifying ratio by the lever member 60 is changed according to the movement quantity of the valve member 41, because the lever member 60 has a plurality of power points which move according to the movement quantity of the valve member 41. The transmission loss of power by the difference of the heat expansion coefficient occurring between the 1st piston 52 as well as the 2nd piston 53, etc., and a housing 10 is reduced, because the displacement and driving force of the Piezzoelectric element 51 are transmitted to the 2nd piston 53 through the oil pressure chamber 54. Also, the lever member 60 can be changed according to a dynamic characteristic that is required for fuel injection equipment 1 and the change of the design is easily performed.