Abstract: A high frequency, hermetically-sealed, semiconductor device with the capability of being cascade-connected with corresponding devices in an advantageous manner. The device consists of a function element which includes at least one semiconductor and other circuit elements necessary for forming a functional amplifier, a DC power circuit for operating the device and high frequency circuits for connecting to corresponding high frequency devices. This device also consists of a metal base substrate, which is used for anchoring the device and mounting other parts of the device thereon, an insulating substrate having a plurality of independent metallized layers used as external contacts and a sealing part for hermetically sealing that part of the insulating substrate which mounts and encloses the function element.