Method for pulling up single crystal

The axial temperature gradient G at the vicinity of the solid-liquid interface in an ingot is calculated in consideration of the heating value of a heater , the dimensions and physical property values of furnace inside components and the convection of the melt before pulling up the single crystal ingot by a puller by use of a numerical simulation of synthetic heater transfers and a numerical simulation of melt convection. Then, the pulling velocity V of the single crystal ingot is determined from an value experienced of the ratio C=V/G of the pulling velocity V and the axial temperature gradient G of the single crystal ingot at which the single crystal ingot becomes defect-free, obtained when the single crystal ingot was pulled up by a same type puller as the puller in the past, and the axial temperature gradient G calculated by use of the simulations. Then, the ingot is pulled up at the pulling velocity, and the change value of the temperature gradient G to the deterioration value of partial furnace inside components roughly measured while the ingot is pulled up is roughly forecasted by use of the simulations. And further, the pulling velocity V of the ingot is adjusted in such a way that the ratio C should become the value experienced according to the change value of the temperature gradient G roughly forecasted.