To prevent, in a resin-sealed type semiconductor package, generation of cracks in a die bonding material used for mounting of a semiconductor chip. A semiconductor chip is mounted over the upper surface of a die pad via a die bonding material, followed by sealing with an insulating resin. The top surface of the die pad to be brought into contact with the insulating resin is surface-roughened, while the bottom surface of the die pad and an outer lead portion are not surface-roughened.