A common mode choke coil includes a differential transmission line including first and second signal lines, a main circuit including a first coil provided in the first signal line, and a second coil provided in the second signal line and connected to the first coil by magnetic field coupling, and a parallel resonance circuit including a third coil connected to both the first and second coils by magnetic field coupling, and a first capacitor electrically connected in parallel to the third coil. In the common mode choke coil, a first resonant frequency of the main circuit is equal or substantially equal to a second resonant frequency of the parallel resonance circuit.