PURPOSE: To obtain a cellulosic fiber having excellent electrical conductivity by blocking hydroxyl groups of a cellulosic fiber with a specific component and conjugating the fiber with a pyrrole polymer.

CONSTITUTION: Hydroxyl groups of a cellulosic fiber are blocked by treating the fiber with a reactive dye or isocyanate having reactivity to the hydroxyl groups. The treated fiber is immersed in a treating liquid composed of a solution containing a pyrrole-type monomer and preferably a dopant (e.g. Lewis acid) and the monomer is polymerized to cover the surface of the fiber with a pyrrole polymer or to impregnate a part or total of the polymer into the fiber. The cellulose fiber is conjugated with the pyrrole polymer by this process to obtain a cellulosic fiber having high electrical conductivity.