A package is used for keeping an electric circuit board with no electronic components provided thereon in an air-tight cavity thereof and for preventing from oxidation during the transportation to the process wherein the electronic components are mounted on the electric circuit board. The cavity is composed of the lower and upper sheet of gas-impermeable materials, which are bonded at the bonded area by the fusion bonding, adhesive agent or viscous agent. The cavity is kept in non-oxidizing atmosphere by filling inert gas or evacuating air therefrom. The lower and upper sheets are composed of single layer or multi-layers, which may be made of flexible material or rigid material. An electric circuit board accommodated in the cavity of the package is taken out by the device comprising a separation roller pair. The device weakens the bonding strength to enable easy pulling of the lower and upper sheets to unpackage the circuit board.