Disclosed herein is a common mode filter that includes a winding core part and first and second wires wound in a same direction around the winding core part. The first and second wires constitute a first winding block on one endmost side in an axial direction of the winding core part, a second winding block on other endmost side in the axial direction of the winding core part, and a third winding block positioned between the first and second winding blocks. The second winding block is a winding block at an odd-numbered position counted from the first winding block. The first and second wires cross each other in an area between the first and third winding blocks and in an area between the second and third winding blocks.