A method of manufacturing a sheet article including a fibrous substrate including microfibers and polyurethane, the manufacturing method comprising the following steps to: a polyvinyl alcohol-adding step of adding a polyvinyl alcohol aqueous solution, which is an aqueous solution of polyvinyl alcohol having the following characteristics, to a fibrous substrate having microfiber expression type fibers as its main constituent to add the polyvinyl alcohol in an amount of 0.1 to 50% by mass based on a mass of the fibers contained in the fibrous substrate, wherein, the polyvinyl alcohol has a saponification degree of 90% or more, as measured according to the method described herein, and an rrr composition abundance ratio of 14.5% or more in a heavy water solvent in tacticity evaluation measured by 13 C-NMR, as measured according to the method described herein, rrr indicating an arrangement of r, in which the adjacent hydroxyl groups of vinyl alcohol units are in different directions, and the abundance ratio being expressed as percentage, assuming that a sum of the integrated values of absorptions is 100%, as measured according to the method described herein a microfiber expression step of, after the preceding step, making microfiber expression type fibers of the fibrous substrate into microfibers having an average single fiber diameter of 0.1 μm to 10 μm, as measured according to the method described herein, a polyurethane-adding step of, after the preceding step, adding water-dispersible polyurethane to the fibrous substrate having the added polyvinyl alcohol; and a polyvinyl alcohol removal step of, after the preceding step, removing the polyvinyl alcohol from the fibrous substrate having the added water-dispersible polyurethane. a polyvinyl alcohol-adding step of adding a polyvinyl alcohol aqueous solution, which is an aqueous solution of polyvinyl alcohol having the following characteristics, to a fibrous substrate having microfiber expression type fibers as its main constituent to add the polyvinyl alcohol in an amount of 0.1 to 50% by mass based on a mass of the fibers contained in the fibrous substrate, wherein, the polyvinyl alcohol has a saponification degree of 90% or more, as measured according to the method described herein, and an rrr composition abundance ratio of 14.5% or more in a heavy water solvent in tacticity evaluation measured by 13 C-NMR, as measured according to the method described herein, rrr indicating an arrangement of r, in which the adjacent hydroxyl groups of vinyl alcohol units are in different directions, and the abundance ratio being expressed as percentage, assuming that a sum of the integrated values of absorptions is 100%, as measured according to the method described herein a microfiber expression step of, after the preceding step, making microfiber expression type fibers of the fibrous substrate into microfibers having an average single fiber diameter of 0.1 μm to 10 μm, as measured according to the method described herein, a polyurethane-adding step of, after the preceding step, adding water-dispersible polyurethane to the fibrous substrate having the added polyvinyl alcohol; and a polyvinyl alcohol removal step of, after the preceding step, removing the polyvinyl alcohol from the fibrous substrate having the added water-dispersible polyurethane.