A magnetic element module includes a magnetic core assembly and at least one first winding structure. The magnetic core assembly includes a first magnetic core and a second magnetic core. The first magnetic core includes a first magnetic slab and a first magnetic post. The second magnetic core includes a second magnetic slab and a second magnetic post. The first winding structure is sheathed around the first magnetic post. The first magnetic post is placed on a second edge of the second magnetic slab. The second magnetic post is placed on a first edge of the first magnetic slab. The first magnetic core, the second magnetic core and the first winding structure are combined together, thereby producing the magnetic element module.