A magnetic element includes a magnetic core assembly and multiple winding coils. The magnetic core assembly is used for proving a closed magnetic flux path and includes a first side plate, a second side plate, a first side pillar, a second side pillar and at least two middle pillars. The first and second side pillars are arranged between the first and second side plates and respectively disposed on bilateral edges of the first and second side plates. The at least two middle pillars are arranged between the first and second side pillars and includes a first middle pillar and a second middle pillar. The winding coils are wound around the at least two middle pillars.