PURPOSE: To prevent the lowering of calculating precision to temp. of a billet temp. caused by temp. of a furnace hearth at the time of inserting the billet in a rotary furnace hearth type heating furnace.

CONSTITUTION: In a control method for extraction billet temp. in the rotary furnace hearth type heating furnace 2 for seamless steel pipe, the furnace hearth 3 temps. at plural points in the heating furnace 2 are continuously calculated based on the actual furnace temp. at each zone in the heating furnace and the positional information of the furnace hearth 3 in the furnace to decide the furnace hearth temp. at the charging position of the billet 4 in the heating furnace. Based on this decided furnace hearth temp. at the inserting position in the heating furnace, the average temp. and the temp. distribution of the billet during heating are calculated and the arithmetic control is executed to the setting furnace temp. at each zone in the rotary furnace hearth type heating furnace 2. By this method, the calculating precision to the billet temp. during heating is improved and the temp. control precision can be improved and the uneven thickness in the peripheral direction at the time of making the pipe can be reduced.