An object of the present invention is to provide a magnetic element where an arrangement area of the element with respect to a mount board is reduced and high density mounting is achieved. The magnetic element 1 is provided with coils 6, a first core 2 and a second core 3, which have outer leg parts 2b and 3b, and middle leg parts 2c and 3c, which are inserted into the coils 6 in plate parts 2a and 3a, and a middle core 4 constituting a closed magnetic circuit disposed to connect the first core 2 and the second core 3 between the first core 2 and the second core 3. When a cross-section in a direction perpendicular to a direction where the outer leg parts 2b of the middle leg part of the first core 2 extend is set to be S1, a cross-section in a direction parallel to a direction where the outer leg parts 2b and 3b of the middle core extend to be S2, and a cross-section in a direction perpendicular to a direction where the outer leg parts 3b of the middle leg part in the second core 3 extend to be S3, the element has a relation of S1<=S3 and S1<=S2.