PURPOSE: A cellulosic high polymer material is treated in a bath containing cupric chloride under heating and reduced to produce the novel tilted high polymer that ia dyeable under usual conditions and has high electrical conductivity without any specific operations.

CONSTITUTION: A cellulosic high-polymer material such as cotton yarn is heat treated in a bath containing cupric chloride, e.g., at 70W110°C with hot water or at 90W110°C with steam, and subjected to reduction treatment by heating it in a solution containing a reductive substance such as sodium dithionite at 60W100°C or by dipping it in a solution containing a reductive substance and steaming at 90W100°C to produce the objective high-polymer material. The product is dyeable under usual dyeing conditions to give the dyed product with no reduction in electrical conductivity.