PACKAGE DEVICE

PURPOSE:To hold and achieve an excellent cooling function with a compact configuration by arranging a metal plate layer in one united body having a coefficient of thermal expansion almost equal to the coefficient of thermal expansion of a wiring board on the rear face of the wiring board inside a second cap. CONSTITUTION:An electronic part element 2 is mounted on one of the main faces of a ceramic wiring substrate 1 and generates heat during operation and drive. A first cap 3 covers the area including the electronic part element 2, and the opening at the end face of the cap is airtight-sealed to the surface of the wiring board 1. A metal plate layer 9 is attached in one united body to the rear surface of the wiring board 1 almost corresponding to the area where the first cap 3 is attached, and its coefficient of thermal expansion is almost equal to the wiring board 1. And the second cap 4 covers the metal plate layer 9; the opening at the end face of the cap is airtight-sealed to the rear surface of the wiring board 1; and cooling is performed by using the absorption of the heat of vaporization or heat of fusion of a cooling medium 5 sealed inside of the second cap 4. By doing this, the package element can have a compact configuration and maintain and achieve excellent cooling function.