The invention provides an electrostatic discharge (ESD) protection device formed by a Schottky diode. An exemplary embodiment of an ESD protection device comprises a semiconductor substrate having an active region. A first well region having a first conductive type is formed in the active region. A first heavily doped region having the first conductive type is formed in the first well region. A first metal contact is disposed on the first doped region. A second metal contact is disposed on the active region, connecting to the first well region without through any heavily doped region being located therebetween, wherein the first metal contact and the second metal contact are separated by a polysilicon pattern disposed on the first well region.