PURPOSE: To provide a semiconductor housing package which makes it possible to airtight-seal a vessel which comprises an insulating base and a metal-made cap perfectly and operate semiconductor elements housed in the vessel in a normal and stabilized manner for long time.

CONSTITUTION: A metal frame 9 is brazed with a metallized metal layer installed to the surface of an insulating base 1 while a metal-made cap 2 is mounted to the metal frame 9, thereby forming a semiconductor element housing package which houses semiconductor elements airtight inside. When the thickness T of the cap 2 is ≥0.25mm, a groove 11 is installed to the lid 2 where the depth (t) of the groove satisfies the relation, 0.9≥t≥0.4T, where T is the thickness of the cap.