This invention provides a duplex-chamber package that has a high level of water vapor barrier properties, can realize mixing of plural contents in a hermetically sealed state, and can reduce the elution of a material contained in the sheet of a duplex-chamber package material into the contents of the package. The duplex-chamber package comprises a package comprising a first sheet superimposed onto a second sheet, the peripheral part of the assembly having been sealed, a weakly sealed part for partitioning the inside of the package into two or more chambers having been provided in a part of the package. The first sheet(I) is a laminated sheet comprising a heat seal layer, a mass transfer layer and a mass transfer blocking layer, and the mass transfer blocking layer being interposed between the heat seal layer and the mass transfer layer. The second sheet (II) is a laminated sheet comprising a heat seal layer, a mass transfer layer, a mass transfer blocking layer and a moisture blocking layer, and the mass transfer blocking layer being interposed between the heat seal layer and the mass transfer layer.
