The invention provides an electrostatic discharge (ESD) protection device having an ESD path between a first circuit and a second circuit. The electrostatic discharge protection device includes a first doped region having a first conductive type. A first well has a second conductive type opposite to the first conductive type. A second doped region and a third doped region are in the first well, respectively having the first and second conductive types. The first doped region is coupled to a power supply terminal or a ground terminal of the first circuit, and the second and third doped regions are both coupled to a power supply terminal or a ground terminal of the second circuit, respectively.