A device to protect a semiconductor device from electrostatic discharge includes a transferring unit transferring the static electricity inputted to said input/output terminal to the power line, a detecting unit sensing the potential difference between both ends of the transferring unit, located between an input/output terminal and one of the power lines, to output the detection voltage, and a discharging unit driven by said detection voltage and discharging the static electricity led to a specific power line to the other power line, and performs the discharging operation smoothly even with minute electrostatic current and a latter part of the static electricity by using the driving voltage, which is used to drive a conventional detecting unit, as the driving voltage of the ESD protection device, thereby safely protecting an internal circuit of a semiconductor device.