The present invention provides a gas separation composite which has high heat resistance and mechanical strength, prevents a support layer from being deformed or damaged by heat during formation of a gas separation membrane and heat during a gas separation operation, and properly supports a gas separation layer to obtain high gas permeability and gas separation properties; and a method of producing the gas separation composite. The gas separation composite includes a metal support having a plurality of through holes in the thickness direction and a gas separation layer laminated on the surface of the metal support. The thickness of the gas separation layer is in a range of 0.1 to 5 µm, the average opening diameter of the through holes of the metal support is in a range of 0.1 to 30 µm, and the opening ratio thereof is in a range of 0.05% to 10%.