A fuel supply device comprises a fuel pump, a set plate, a control circuit, and an electrical wiring member. The fuel pump is disposed within a fuel tank. The set plate closes an opening of the fuel tank. The set plate comprises a controller chamber isolated from the fuel tank. The control circuit is disposed within the controller chamber. The control circuit controls the fuel pump. The electrical wiring member connects the control circuit and the fuel pump. The electrical wiring member is arranged from an interior of the controller chamber to an interior of the fuel pump and is passed through the set plate. A part of the electrical wiring member is exposed to the atmosphere. Furthermore, the exposed part is disposed within a range from the interior of the fuel tank to the interior of the controller chamber.