The present invention provides a common mode choke coil that has a higher coupling factor than that of a conventional common mode choke coil and that is easy to be assembled. A common mode choke coil according to the present invention includes a first coil portion 51 and a second coil portion 52 that are connected to each other in series, and a third coil portion 53 and a fourth coil portion 54 that are connected to each other in series. The first coil portion 51 and the second coil portion 52 are respectively disposed in the first quadrant and the third quadrant of an orthogonal coordinate system and housed in a first bobbin 8a, and the third coil portion 53 and the fourth coil portion 54 are respectively disposed in the fourth quadrant and the second quadrant of the orthogonal coordinate system and housed in a second bobbin 8b. The first bobbin 8a and the second bobbin 8b are fitted to each other, and thereby adjacent case portions of the two bobbins are bonded to each other.