To provide a method for producing a conductive nonwoven fabric which is a nonwoven fabric consisting essentially of synthetic fibers, having ≤10% mixing ratio of carbon fibers and usable for detecting water leakage sites of waterstop sheets in industrial waste disposal sites in a usual production process of nonwoven fabrics.

The method for producing the conductive nonwoven fabric is carried out as follows. Chopped fibers of the carbon fibers are mixed with general-purpose synthetic fiber staples in (1/99) to (10/90) mass ratio and opened and a plurality of the resultant card webs are laminated and pre-punched by a needle punching method. A plurality of pre-punched laps obtained by the previous punching are further laminated and then subjected to finish punching by the needle punching method. In the method, electrical resistance between two points separated by a prescribed distance is measured on the pre-punched laps prepared by the previous punching and the pre-punched laps having the measured value within a prescribed range are fed to the next step and subjected to the finish punching in the method for producing the conductive nonwoven fabric.