The present invention relates to an apparatus for alleviating a transcutaneous pain using electrical stimulation, which comprises: an output unit for generating a packet waveform in an amplitude and frequency range corresponding to a random number value randomly generated within a preset range； an electrode cable having one end thereof connected to a cable terminal provided in a main body, and applying an output value applied from the output unit to a pair of electrodes connected to the other end thereof； and a pair of electrodes for applying an output of the output unit to an affected area by being connected to a snap terminal provided at an end of the electrode cable. The output unit includes: a cable terminal for connection with the electrode cable； a random number generating module for generating a random number value within a preset range； and an output module for generating the packet waveform in the amplitude and frequency range corresponding to the random number value. According to the present invention, the packet waveform in the amplitude and frequency range varied in accordance with an output value of a random number generator is applied to an affected area. In addition, when an ADC value of an output terminal exceeds a preset reference, it is determined that the electrodes are detached from the affected area to stop the output of the packet waveform and to output an open error. In addition, when the ADC value of the output terminal is less than a preset reference, a short error is output since the electrodes are attached to each other. The connector is provided at a front end of the electrodes connected to equipment through the cable, thereby disturbing a pain transfer of a central nervous system not to recognize an intractable chronic pain, a cancerous pain, an extreme pain after surgery, a neuralgia or muscular pain. Furthermore, a short-circuit between the electrodes and the affected area can be immediately checked, and a problem of replacing the cabl
