To provide a fuel injection device which improves and simplifies the valve control for the fuel and an additive liquid.

In this fuel injection device for an internal combushion engine, a two-fluid injection nozzle 12 is provided, and the fuel and an additive liquid can be fed alternately to the pressure chamber 11 of the two-fluid injection nozzle 12. A valve device is provided, by which a fuel at the high pressure side can be fed to the two-fluid injection nozzle 12, and the connection of the pressure chamber 11, and a feeding duct 26 of the low pressure side and the additive liquid can be controlled. In such a system of fuel injection device, a single change-over valve 16 is provided. This change-over valve 16 is formed to control the load owing to the high pressure or the low pressure of the pressure chamber 11, and to control the filling of the pressure chamber 11 with the additive liquid.