To provide a method for efficiently producing a pipe lining material for lining the inner surface of an aged pipe line.

A tubular fibrous resin absorbent 1 is passed through a plastic tube 3, and the absorbent 1 is passed through a cylindrical heater 4. A core member 5 is put in the absorbent 1 and held in the space of the central part of the heater 4 by wires passed through the absorbent 1. The absorbent 1, the heater 4, and the core member 5 are moved relatively, while expanding pressure is applied in turn to the inner surface of the absorbent 1 from its one end side over the other end side, the plastic tube 3 adherent to the outer surface of the absorbent 1 by the pressure is heated by the heater 4, and the plastic tube 3 is welded in turn to the outer surface of the absorbent 1. In this way, a thin film 2 having a uniform thickness by the plastic tube 3 can be formed on the outer surface of the absorbent 1.