PURPOSE: To easily and inexpensively mold multiple pin lead frame to be associated with an ultrahigh speed, high capacity semiconductor device by forming lead inner ends in a multi-finger array state by etching, coining it, and increasing in width a bonding surface.

CONSTITUTION: Two inner ends 1a, 1a of a lead frame are reduced in width W'' of the ends 1a by etching, and a pitch P between the ends 1a and 1a is reduced to be molded that much. Then, the ends 1a are reduced in thickness T'' by coining for collapsing the ends 1a, 1b of the lead frame A by pressing while holding the pitch P as it is. The ends 1a are widened at the width W'' to W upon reduction of the thickness T, the sides are externally extended to reduce a space S'' to S between the ends 1a and 1a. The upper faces of the inner ends 1a are used as bonding surfaces.