An inductor, a circuit board and a method for forming an inductor are provided. The inductor comprises: a first pad arranged on a first metal wiring layer of a circuit board; a second pad arranged on a second metal wiring layer of the circuit board; and a first hole with conducting medium filled therein, one end of the first hole being located in the first pad and the other end thereof being located in the second pad. The inductor can effectively reduce the area of the circuit occupied by the inductor.