A method controls a resistivity of a grown silicon single crystal by using a dopant when the silicon single crystal is grown by CZ method, including the steps of initially doping with a primary dopant such that the silicon single crystal has a predetermined conductive type and additionally doping with a secondary dopant having a conductive type opposite to that of the primary dopant continuously or intermittently, according to a solidification rate expressed by (crystalized weight)/(initial weight of silicon raw material) while growing the silicon single crystal, wherein in the additional doping step, the additional doping with the secondary dopant is carried out when the solidification rate is a predetermined value α or more, while the crystal is not doped with the secondary dopant until the solidification rate reaches the predetermined value α.