the silicon single crystal was pulled at a pulling rate of 1 4 mm min where the pulling rate is an average pulling rate when a straight body portion of the silicon single crystal was pulled the oxygen concentration in the straight body portion after pulling was about 19 ppma u00b1 1 2 ppma jeida thus it was demonstrated that when the heater and the shield were lowered together the silicon single crystal under growing could be cooled efficiently and the average pulling rate could be increased compared with comparative example 1 described later the oxygen concentration in the straight body portion after pulling was in a range equal to comparative example 1 described later pulling of a silicon single crystal was performed under the same condition as in example 1 except for using a silicon single crystal pulling apparatus 101 in which a heater 104 is movable vertically but a shield 105 is not movable vertically as shown in fig3 in this example as shown in fig3 the upper end position of the heater 104 was below the upper end position of the crucible 103 but the shield 105 was in a high position relative to the heater 104 since the shield 105 is not movable as a result the average pulling rate when a straight body portion of the silicon single crystal was pulled was 1 1 mm min which was lower than the average pulling rate in example 1 described later moreover the oxygen concentration in the straight body portion after pulling was about 19 ppma u00b1 1 2 ppma the reason is considered that since only the position of the heater was changed while the position.