A surface-mount type over-current protection element includes two single-layer composite chips, wherein one chip is made of a first core material and a first and a second metallic foil layer attached on the two surfaces of the first core material, the other chip is made of a second core material and a third and a fourth metallic foil layer attached to the two surfaces of the second core material. The protection element also has an insulating layer arranged between the two chips to electrically insulate and bond to the second and third metallic layers to form a bi-layer composite chip. Part of the first metallic foil layer and the corresponding part of the fourth metallic foil layer are etched to expose part of the first core material and correspond part of the second core material. One or more through-holes are made on the bi-layer composite chip for mounting.