A method of manufacturing a reinforcing fiber sheet includes the following steps (a) to (c). In the first step, a screen having a mesh size which is coarser than a standard mesh size is set on top of a cloth layer constructed of vertically and horizontally woven vertical strips and horizontal strips which are assemblages of numerous reinforcing fibers. In the second step, an ink that exhibits good flexibility after drying is supplied onto the screen in a screen printing, and the cloth layer is impregnated with the ink. In the third step, the cloth layer impregnated with the ink is dried to form a cloth core. This cloth core is embedded in a matrix resin and used as a reinforcing material for a molded article, or a synthetic resin high-stretch sheet material and the resulting assembly is used as a material for dress-up sheets.