PURPOSE: To perform uniform annealing and to facilitate bending by annealing and bending the tip of a primary winding flat spiral spring supplied in sequence while it is carried, then, carrying it to the following stage.

CONSTITUTION: The straight part 2b of the primary winding 2 which is reached to a tip annealing basver by intermediate carriage is annealed in sequence in an intermediate operation. When the primary winding whose straight part is annealed arrives at a bending machine, a positioning cylinder 72 operates, the straight part 2b of the primary winding 2 is pushed back by a pressing block 72c and the straight part 2b is positioned to the position which protrudes a specified amount from a bending base 75. When a clamp cylinder 73 operates and a piston rod 73c is opened, a rod 73c is lowered. Consequently, the straight part 2b of the primary winding 2 positioned at the specified position is pressed by the pressing block 73b on the bending base 75. Thereafter, a bending cylinder 74 operates, a bending rod 74b falls, the straight part 2b of the primary winding 2 which protrudes a specified amount from the bending base 74 is bent and a bent piece 2d is formed at the tip of the straight part 2b.