An apparatus for manufacturing polycrystalline silicon whereby raw-material gas is supplied to one or more heated silicon seed rods provided vertically in a reactor so as to deposit the polycrystalline silicon on a surface of the silicon seed rod, having a seed rod holding member, made of conductive material, having a holding hole in which a lower end of the silicon seed rod is inserted, the holding hole having a horizontal cross-sectional shape with at least two corners, and the holding member having a screw hole extending from the outer surface of the seed rod holding member to at least the holding hole and formed at the location of at least two corners of the holding hole; and a fixing screw which fixes the silicon seed rod and is threaded through at least one of the screw holes.