PURPOSE: To reduce the cost by forming the conductive film of the lead, etc., of film carrier tape by using electroless plating.

CONSTITUTION: After forming a reducer layer 18a on an insulating film 1 by screen printing, the layer is substituted by activator liquid so as to form a catalyst metal layer 18b, a metal film 19 is formed on the catalyst metal layer 18b by electroless plating and a conductor film such as a lead is formed. The process is simplified compared with the conventional production which uses photolithographical technic and the cost is reduced. The conventional photolithographical technic required to expose a pattern one by one, however, the screen printing manufactures a plurality of patterns at one time and the productivity is improved and the cost is reduced.