A magnetic element includes a first wire, a second wire, a third wire, a fourth wire and a first single-strand wire. The first wire is disposed at a first side of the magnetic element, and has a first end and a second end. The second wire is disposed at the first side of the magnetic element, and has a third end and a fourth end. The third wire is disposed at a second side of the magnetic element, and has a fifth end and a sixth end. The fourth wire is disposed at the second side of the magnetic element, and has a seventh end an eighth end. The first single-strand wire has one terminal simultaneously connected to the second end and the fourth end.