According to the invention, a press roller device (1) for moulding a grooved structure inside a tubular workpiece (7) has several press rollers (4, 5, 6), said press rollers rotating around a form tool (2) and being staggered axially in relation to one another. At least two of the press rollers (4, 5) are driven in opposite directions to each other. This arrangement prevents the workpiece from twisting to a large extent.