Disclosed is a gas-barrier thin film laminate which can be produced with high yield while having higher gas barrier properties than the conventional ones. The gas barrier properties of this gas-barrier thin film laminate do not deteriorate even when the laminate is bent. Also disclosed is an organic EL device (hereinafter also referred to as OLED) with excellent environmental resistance which uses the gas-barrier thin film laminate. The gas-barrier thin film laminate having at least one inorganic film and at least one stress relaxation film is characterized in that at least one stress relaxation film is formed by an atmospheric pressure plasma method wherein two or more electric fields of different frequencies are applied.