Aimed at stably forming sheared surfaces of leads of semiconductor devices, and at raising ratio of formation of plated layers onto the sheared surfaces of the leads, a lead cutter has a die 106, and a cutting punch 110 having a cutting edge at least on the surface facing the die, wherein clearance T between the die 106 and the cutting punch 110 is set within the range from not smaller than 2.3% and smaller than 14.0% of the total thickness of the leads to be cut and plated layers formed on the upper and the lower surfaces thereof.