The present invention utilizes a silicon member (single-crystalline silicon rod), which is cut out from a single-crystalline silicon ingot which is grown by a CZ method or FZ method, as the core wire when manufacturing a silicon rod. Specifically, a planar silicon is cut out from a body portion which is obtained by cutting off a shoulder portion and a tail portion from a single-crystalline silicon ingot and is further cut into thin rectangles to obtain a silicon bar. In the case that the crystal growth axis orientation is <100>, there are four crystal habit lines, and the silicon bar is cut out such that the surface forms an off-angle .theta. in a predetermined range with the crystal habit line. The provided polycrystalline silicon rod has a low impurity contamination and high single-crystallization efficiency.