A polycrystalline silicon rod characterized by having a half value width of the X-ray diffraction pattern peak showing a crystal orientation (111) of not more than 0.3 DEG , an internal distortion factor in the radial direction of less than 5.0 x 10 cm , and an internal iron concentration of not more than 0.5 ppba. Such a high-crystallinity, high-purity and low-internal distortion polycrystalline silicon rod is prepared by heating a silicon core material in a gaseous atmosphere comprising trichlorosilane and hydrogen to deposit silicon onto the silicon core material to prepare a polycrystalline silicon rod and then heat treating the rod out of contact with the open air to reduce an inherent strain.