To provide a package for high frequency circuit component housing wherein a good transmission characteristic is acquired also in a high frequency region of a submillimeter wave band of at least 25 GHz in a lid which is composed of an insulator.

The package 1 for high frequency circuit component housing is provided with an insulating substrate 2 which has the loading portion 2a of a high frequency circuit component 4 used in 25-90 GHz frequency region on an upper surface, and the lid 3 which is bonded to the upper surface of the insulating substrate 2 with a sealing agent 9 so as to surround the loading portion 2a, has a recess on a lower surface and is composed of ceramic. A high frequency circuit component 4 is airtightly accommodated inside a vessel constituted of the insulating substrate 2 and the lid 3. When the height of the side wall of the lid 3 is made T (mm), the thickness of the side wall of the lid 3 is made W (mm) and an effective wavelength inside the lid 3 of a high frequency signal used in the high frequency circuit component 4 is made λ (mm), a relation of T<λ/2 or W<λ/4 is established.