An apparatus, as an electromagnetic wave back introduction blocking module connected between an ignition (IG) system and a converter, includes a front capacitor module which includes a first coil part including one or more coils having one side connected to the IG system in series and a first capacitor part connected between the other side of the first coil part and a ground, a central coil module which includes a second coil part including one or more coils having one side connected to the other side of the first coil part and a second capacitor part connected between the other side of the second coil part and the ground, and a rear capacitor module which includes a third capacitor part having one side connected to the other side of the second coil part. The rear capacitor module is connected to the converter.