PURPOSE: To obtain a resin-sealed type semiconductor device of high reliability by a method wherein a plurality of fine narrow grooves having a cross-sectional shape which has been overhung only in a direction perpendicular to a bending direction of a lead frame are made at the inside and outside of an end face part of a resin layer of the lead frame coming into contact with the resin layer.

CONSTITUTION: A 42% Ni-Fe alloy sheet (40×300×0.5t) is irradiated with a laser beam; four U-shaped parts each with a depth of 0.2 and a width of 0.2 and at an interval of 0.5mm are made on the rear; after that, this sheet is plane-rolled in a direction of the U-shaped grooves; a sheet of 0.2 (t) is formed; a cross-sectional shape of the U-shaped parts has an overhung U-shaped part 5 and a friction interface 6 at its deep part. A lead frame is stamped from this sheet; an IC is installed in its center; a resin-sealed type, semiconductor device is manufactured; two grooves each are situated on the lead frame at the inside and the outside of an end face of a resin- sealed body; a solder is inserted or bonded at the inside and its circumference of the grooves outside the resin-sealed type semiconductor device; after that, the lead frame is bent and pins are formed. As a result, a semiconductor whose resistance to exfoliation and to moisture penetration is excellent can be obtained; the resin-sealed type semiconductor device of high reliability can be obtained.