Provided is a gas barrier laminate film capable of realizing excellent gas barrier property, water resistance, and adhesiveness, having a plastic substrate (A), a silicon oxide layer (B) formed on at least one surface of the plastic substrate (A), and a coat layer (C) formed by applying a coating solution onto a surface of the silicon oxide layer (B), wherein the coating solution comprises a mixture of a polyurethane-based resin (c1) and a silane coupling agent (c2) and contains a reaction product of (c1) with (c2) as a main component; and a number-average molecular weight of the reaction product is in the range of 100,000 to 1,000,000.