Abstract: An over-current protection device comprises a resistance material with positive or negative temperature coefficient and an upper surface and a lower surface; a first electrode layer having a first groove, disposed on the upper surface; a first surface mount pad disposed on the upper surface; a second electrode layer disposed on the lower surface, electrically connecting to the first surface mount pad; a second surface mount pad disposed on the lower surface, electrically connecting to the first electrode layer; a second groove electrically separating the fist surface mount pad from the first electrode layer; and a third groove electrically separating the second electrode layer from the second surface mount pad. The first groove divides the first electrode layer into two connected regions. The first and second surface mount pads are separated from each other and one end of the first groove connects to the second groove.