PURPOSE: To omit an excess length processing member in a connection box by contracting a storing container in a drawing end so that excess length forms a loop with a small bending radius and expanding the storing container in a connection box so that the excess length forms a loop with an allowable bending radius.

CONSTITUTION: The bending radius r2 formed at the time of expanding the storing container 30 and storing the excess length 17 of an optical fiber core 16 in the container 30 like a loop is ≥30mm of an allowable value. In case of contracting the excess length 17 and storing it in a drawing end protection tube 22, the loop of the excess length 17 is distorted and the bending radius is turned to r1 (e.g. 20mm). After completing laying and releasing the drawing end, the storing container 30 is expanded, returned to the original state and stored in the connection box, so that the radius r2 is turned to ≥30mm the allowable value. Consequently, it is unnecessary to newly execute excess length processing in the connection box.