A semiconductor device has: a low concentration drain region creeping under a gate electrode of a MIS type transistor; a high concentration drain region having an impurity concentration higher than the low concentration drain region and formed in the low concentration drain region spaced apart from the gate electrode; and an opposite conductivity type region of a conductivity type opposite to the drain region formed in the low concentration drain region on a surface area between the high concentration drain region and the gate electrode, the opposite conductivity type region and low concentration drain region forming a pn junction.