An electromagnetic generating device is used for testing an electromagnetic interference of electronic elements of an electronic device. The electromagnetic generating device includes a power source and a detector. The power source includes a power output. The detector includes a first magnetic guiding portion, a second guiding portion, and an electronic coil. The first magnetic guiding portion is connected to the second magnetic guiding portion. The electronic coil surrounds the second magnetic guiding portion. The electronic coil includes an input coupled to the power output of the power source, and an output being grounded.