An optical cable having a metal tube receiving an optical fiber and bent to form a waved shape is disclosed. The optical cable may prevent cutoff of the optical fiber or deterioration of optical characteristics though tensile force is applied to the optical cable in its longitudinal direction since the metal is formed in a waved shape. To bend the metal tube, the metal tube is passed through roller pair(s) which are shaken in a direction perpendicular to the advancing direction of the metal tube. Thus, it is possible to obtain excess fiber length (EFL) easily and accurately as desired.