A gas barrier packaging material precursor (10) of the present invention, includes: a support (1); an adhesion layer (2) provided on one surface of the support (1); and a barrier layer (3) and a protective layer (4) formed adjacent to each other on the adhesion layer (2). The adhesion layer (2) contains a composite of a silicon compound having any one of an isocyanate group, an amino group, or a mercapto group or a hydrolysate thereof, an acrylic polyol, and an isocyanate compound. The protective layer (4) is formed of a coating liquid containing a polyvalent metal compound, a polyester resin, and a dispersant. The protective layer (4) contains the polyvalent metal compound by 40 to 90 mass% relative to 100 mass% of the protective layer (4). When the barrier layer (3) is separated from the gas barrier packaging material precursor (10) to measure an infrared absorption spectrum of the barrier layer (3) by a transmission method, a ratio (±/²) of a maximum peak height (±) of absorbance in a range of 1490 to 1659 cm -1 to a maximum peak height (²) of absorbance in a range of 1660 to 1750 cm -1 is less than 1.