The present invention provides a cylindrical secondary battery which can have increased safety and capacity, and enhanced scratch resistance and pressure resistance on an external contact surface. To this end, a cylindrical secondary battery is disclosed, the battery comprising: a cylindrical case; an electrode assembly received in the case; and a cap assembly for sealing the case, wherein the cap assembly comprises a top plate having a notch formed on at least one surface thereof, a middle plate coupled to the top plate and including a first through-hole formed through the center thereof, and a bottom plate electrically connected with the electrode assembly and coupled to the top plate through the first through-hole of the middle plate, and includes a surface-treated region formed by surface-treating a surface of the top plate so as to have a concave-convex structure.