A yarn mainly configured by expanded graphite is improved to be so highly flexible that the expanded graphite does not protrude in a usual bending process, in order to prevent partial missing of the expanded graphite from occurring when the yarn is twisted or braided to produce a gland packing. A yarn 1  for a gland packing is formed by filling the interior of a tubular member 3  configured by knitting or braiding an inconel wire 2  having a diameter of 0.1 mm, with fibrous expanded graphite 4  having a section in which an aspect ratio is set to 1 to 5, the aspect ratio being a value obtained by dividing the width w by the thicknesst.