Common mode filter

A common mode filter which is installed in a circuit board comprising an arrangement hole penetratingly formed in a predetermined area to be positioned in the arrangement hole, comprising:

• a ring-shaped magnetic core made of a magnetic material;
• a plurality of coils wound around an outer surface of the magnetic core;
• and a base member to which the magnetic core is coupled, and having a plurality of connector members for electrically connecting the plurality of coils wound around the magnetic core to the outside, wherein the base member is installed such that a portion thereof is caught on an edge side of the arrangement hole, wherein the base member includes a ring-shaped body in which a hollow portion is formed, a connecting member which is formed on the body to cross the hollow portion and a pair of coupling grooves which are formed by entering a certain depth from one surface of the connecting member such that a portion of the magnetic core can be inserted,
• wherein the base member further includes at least two extension parts protruding outward from the body by a predetermined length and having one surface forming a stepped surface with one surface of the body, wherein one surface of the extension part forming the stepped surface with one surface of the body includes a first portion extending from the body and a second portion extending from the first portion such that a first stepped surface and a second stepped surface having different heights may be formed, respectively, and wherein the second stepped surface is installed to be caught on an edge of the arrangement hole.