Foreign matter formed over (or adhered to) a surface of a lead is reliably removed. A laser beam is applied to a residual resin (sealing body) which is formed in (or adhered to) a region surrounded by a sealing body (a first sealing body), a lead exposed (projected) from the sealing body, and a dam bar. The foreign matter formed over (or adhered to) the surface of the lead can be reliably removed by washing the surface of the lead after the removal of the residual resin. Thus, in a subsequent plating step, the reliability (wettability, adhesion with the lead) of a plating film to be formed over the surface of the lead can be improved.