A high voltage device includes: a semiconductor layer, a well, a body region, a body contact, a gate, a source, and a drain. The body contact is configured as an electrical contact of the body region. The body contact and the source overlap with each other to define an overlap region. The body contact has a depth from an upper surface of the semiconductor layer, wherein the depth is deeper than a depth of the source, whereby a part of the body contact is located vertically below the overlap region. A length of the overlap region in a channel direction is not shorter than a predetermined length, so as to suppress a parasitic bipolar junction transistor from being turning on when the high voltage device operates, wherein the parasitic bipolar junction transistor is formed by a part of the well, a part of the body region and a part of the source.