Abstract: Dust particles generated in a circular knitting machine and a knit fabric manufacturing apparatus, which comprises a circular knitting machine and creels, are collected, thereby preventing the breakage of yarns and maintaining the quality of a knit fabric. There is provided an outer casing which is provided at the upper portion of the circular knitting machine and is open at the lower surfaces thereof and a dust collecting body which is provided inside the outer casing and has a cylindrical filter on which suction operation acts. There is provided an adjusting plate having a cylindrical portion between a knitting portion of the circular knitting machine and the dust collecting body, thereby sucking air including dust from the knitting portion. There is fixed a ring plate to the upper outer portion of the cylindrical portion, thereby sucking air including the dust from the portion close to the yarn supply device other than the knitting portion and the sucked air is cleaned by the filter.