Fuel Injection Device

To provide a fuel injection device capable of improving waterproof performance of the coil portion. A fuel injection device includes a coil bobbin disposed in a housing and having a bobbin outer peripheral surface that holds a coil and a bobbin inner peripheral surface that is a surface on an opposite side of the bobbin outer peripheral surface and a first outer peripheral surface and a first outer peripheral surface (guide portion) that come into contact with the bobbin inner peripheral surface A first space S and a second space S (internal space) are formed by the first outer peripheral surface and the first outer peripheral surface and the bobbin inner peripheral surface and the first space S and the second space S communicate with a space filled with the connecting portion