Common mode filter

The technical problem of the present invention is to provide a common mode filter that improves the symmetry between a pair of windings. A common mode filter (1) has conductor layers (L1, L2). The conductor layer (L1) includes a coil pattern (C1), a connection pattern (11), and a lead-out pattern (51). The conductor layer (L2) includes a coil pattern (C2), a connection pattern (22), and a lead-out pattern (52). The winding directions of the coil patterns (C1, C2) are the same as each other. The lead-out pattern (51) is longer than the lead-out pattern (52), and the diameter of the coil pattern (C2) is larger than the diameter of the coil pattern (C1). Thus, the difference in resistance between the windings due to the difference in length between the lead-out pattern (51) and the lead-out pattern (52) is offset by the difference in diameter between the coil pattern (C1) and the coil pattern (C2), and therefore, the symmetry between the pair of windings can be improved. 本发明的技术问题在于，提供了一种提高一对绕线间的对称性的共模滤波器。共模滤波器(1