An inductor device includes a first trace, a second trace, a third trace, a fourth trace, and a double ring inductor. The first trace is disposed in a first area, and located on a first layer. The second trace is disposed in the first area, coupled to the first trace, and located on a second layer. The third trace is disposed in a second area, and located on the first layer. The fourth trace is disposed in the second area, coupled to the third trace, and located on the second layer. The double ring inductor is disposed on the first layer, located at outer side of the first trace and the third trace, and coupled to the first trace and the third trace.