The invention is aimed at providing a bonding structure of a copper-based bonding wire, realizing low material cost, high productivity in a continuous bonding in reverse bonding for wedge bonding on bumps, as well as excellent reliability in high-temperature heating, thermal cycle test, reflow test, HAST test or the like. The bonding structure is for connecting the bonding wire onto a ball bump formed on an electrode of a semiconductor device, the bonding wire and the ball bump respectively containing copper as a major component thereof. The bonding structure comprises a concentrated layer A provided at an interface of a bonding part of the ball bump and the bonding wire, wherein the concentration of a metal R other than copper in the concentrated layer A is not less than ten times the average concentration of the metal R in the ball bump; and a concentrated layer B provided at an interface of a bonding part of the ball bump and the electrode, wherein the concentration of the metal R in the concentrated layer B is not less than ten times the average concentration of the metal R in the ball bump.