Abstract: A method for manufacturing a seat for use in an automobile, airplane and the like is disclosed which comprises the steps: knitting at least two kinds of synthetic fibers respectively having different average heat setting temperatures to form a bag-shaped trim cover assembly of a size suitable for covering a pad of foam material; covering the foam pad with the thus-formed trim cover assembly; and then heat-setting both the trim cover assembly and the pad at temperatures necessary for the trim cover assembly to shrink sufficiently so that the trim cover assembly can be brought into close contact with the surface of the pad.