PURPOSE: To realize a package with an excellent hermetic feature by a method wherein two sides of a tab mounting a semiconductor element are provided with tab leads whose ends connect to an outer frame and the other two sides are made to approach by several external leadout leads that are connected with each other by dams supported by the outer framework and protrusions are installed halfways in the tab leads before the application of a sealing resin.

CONSTITUTION: Both ends of a tab 1 mounting a semiconductor element are provided with tab leads 2 extending from two sides of the tab 1 to be connected to an outer frame 5 provided with a guide hole 6. The other two sides of the tab 1 are approached by a plurality of external leadout leads 3 that are linked to dams 4 positioned parallel to the tab leads 2 and the ends of the dams 4 are commected to the outer frame 5. Before application of a resin to the framework for sealing for the completion of the package, protrusions 7 are provided halfways on the tab leads 2 to alleviate the sliding property, expected to occur between the tab leads 2 and the sealing resin when the outer frame 5 are cut away, so as to reduce the lowering of the humidity-resisting feature due to the slide.