A magnetic secure transmission (MST) device which generates an MST signal includes a first transmitter, a first coil that generates a first signal depending on an operation of the first transmitter, a second transmitter that operates at an operating frequency of the first transmitter, and a second coil that generates a second signal for offsetting or compensating for the first signal depending on an operation of the second transmitter. The MST signal is generated as the first signal and the second signal overlap each other.