To obtain a method for growing an undislocated, large-diameter and high-weight silicon single crystal without causing the single crystal to fall into a molten liquid in the growing of the silicon single crystal by the Czochralski method.

A <100> crystal having a diameter of 12.7 mm is brought into contact with the surface of a silicon molten liquid, and a neck part having a diameter of 3 mm and a length of 100 mm is formed, and the tip of the neck part is undislocated. Then melt back is performed from the silicon molten liquid contact surface of a seed crystal to the position of 20 mm (L≥L'=12.70×tan54.74°=12.70×1.41=17.96 mm) without disconnecting the tip of the neck part from the molten liquid. Then the silicon single crystal having a diameter of 300 mm and a length of 1,000 mm is grown by extending in diameter to the diameter of 300 mm without growing the neck part.