PURPOSE: To eliminate the necessity for covering an optical fiber unit with a metal tube and prevent the optical fiber unit from being damaged by welding by storing the unit in a groove between the adjacent elementary wires or a groove formed by elementary wires.

CONSTITUTION: An optical fiber composite stranded wire conductor is provided by using the following methods (1) or (2):(1) in the groove formed between elementary wires layer stranded, e.g. aluminium covered steel wire 5 and aluminium wire 4a an optical fiber unit made of one or a plurality of optical fiber elementary wires onto which protection cover is formed is stored; or (2) elementary wires formed with grooves preliminarily formed in the longitudinal direction are stranded with the grooves facing the outside, and in the grooves is stored an optical fiber unit (1) made of one or plural optical fiber elementary wires onto which protection cover is applied.