A method for producing a reinforcing fiber woven fabric of the invention is a method for producing a reinforcing fiber 1 for weaving the reinforcing fiber as at least a warp 2. The yarn width of at least the warp 2 constituting the woven fabric is widened in the direction of the weft 3 by reciprocating cylindrical bodies 4 in the direction of the warp 2 of the woven fabric while rolling the cylindrical bodies 4 in a pressurization state to the woven fabric 1 A apparatus for producing a reinforcing fiber woven fabric of the invention comprising: a guide roller 5 which comes into contact with the surface of a reinforcing woven fabric continuously passing through at a predetermined winding angle and rotates; a plurality of cylindrical bodies 4 rotatably supported on the woven fabric which comes into contact with the surface of the guide roller 5; and driving parts 6 to 10 for reciprocating the cylindrical bodies in the direction of the warp 2 of the woven fabric.