The present disclosure provides a high voltage semiconductor device includes a substrate, a first well region, a second well region, a source, a drain, a first electrode structure and a second electrode structure. The first well region and the second well region are disposed in the substrate, and which includes a first conductive type and a second conductive type which are complementary with each other. The source and the drain are respectively disposed within the first well region and the second well region. The first electrode structure and the second electrode structure are both disposed on the substrate, and the distance between the top surface of an electrode of the first electrode structure and the top surface of the substrate includes a first height and a second height which are different from each other.