NOVELTY - The method involves installing electroconductive bottomless cooling mold (2) in which portion of axial direction is divided into multiple portions in circumferential direction in induction coil (1). Silicon raw material is dissolved by electromagnetic induction within bottomless mold. The melted silicon is pulled down and is solidified. A dummy bar (4) by which silicon (5) is bonded with upper surface of dummy-bar main portion (4a) is used for supporting silicon raw material when initial stage dissolution of silicon raw material is performed in bottomless mold.    USE - Manufacturing method of polycrystalline silicon used as substrate material of solar cell.    ADVANTAGE - The contact with initial stage raw material, silicon nitride and carbon dummy bar can be eliminated when initial stage dissolution of the silicon raw material is performed. Thus the generation of the foreign material in ingot top portion can be prevented. The manufacture yield of the ingot can be improved. Since there is no need to remove carbon dummy bar from ingot after casting, the damage of the dummy bar can be avoided. The manufacturing cost can be reduced. The life of the carbon dummy bar can be extended. The amount of wastage of silicon raw material can be reduced. The man-hour can be reduced.    DETAILED DESCRIPTION - The silicon raw material dissolved at the time of initial stage dissolution is made to flow into a recess which is formed by a recess formation element (4b). The cross-sectional area (SA) of a portion where silicon ingot and dummy bar contacts is smaller than the cross-sectional area (SB) of the silicon ingot of regular casting portion. Silicon is solidified, and dummy bar and silicon ingot are bonded together during casting. The silicon ingot is separated from dummy bar after casting. The grinding of surface which opposes mold wall of dummy bar is performed after separating the silicon ingot. The dummy bar obtained by cleaning and drying process by an acid is used.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of the polycrystalline silicon.    Induction coil (1)    Mold (2)    Dummy bar (4)    Dummy-bar main portion (4a)    Recess formation element (4b)    Silicon (5)    Cross-sectional areas (SA,SB)