To provide a lead frame which can be manufactured through simplified processes.

A lead frame is equipped with a conductive board 1, leads 3 and 3' which are two-dimensionally formed by plating on the conductive board 1, an insulating film 4 which is formed on the surface of the board 1 where the leads 3 and 3' are provided, openings provided to the insulating film 4 corresponding to the leads 3 and 3' so as to make them exposed, external terminals 5 each provided to the openings, and a die pad 6 which is obtained by selectively etching the conductive board 1 so as to support a semiconductor element, where the conductive board 1 functioning as a feeder layer when plating is carried out is made to serve as a reinforcing plate. Therefore, a stiffener serving as a reinforcing plate is not required to be bonded through a separate process, and a stiffener and a ground layer can be formed through the same process with which a wiring layer and a grounding layer are formed.