An electrostatic discharge (ESD) protection device includes a semiconductor substrate and a pair of first well regions formed in the semiconductor substrate, wherein the pair of first well regions have a first conductivity type and are separated by at least one portion of the semiconductor substrate. In addition, the ESD protection device further includes a first doping region formed in a portion of the at least one portion of the semiconductor substrate separating the pair of first well regions, having a second conductivity type opposite to the first conductivity type. Moreover, the ESD protection device further includes a pair of second doping regions respectively formed in one of the first well regions, having the first conductivity type, and a pair of insulating layers respectively formed over a portion of the semiconductor substrate to cover a portion of the first doped region and one of the second doping regions.