To provide a device for adding a turbulent flow to a papermaking raw material so as not to generate lumps for producing a uniform paper in the wide range of class of the paper.

This turbulent flow-forming device is equipped with turbulent flow blades 28 having a variable entry angle β for generating the turbulent flow to a papermaking raw material on passing the raw material through a papermaking machine with a porous conveyer 18 of the papermaking machine, actuating devices 112, 114, 120, 122 for adjusting the entry angles of the blades against the porous conveyer 18 to control the turbulent flow, sensors 50, 32, 24 positioned adjacently to the porous conveyer and on the downstream of the blades so as to generate corresponding sensor output signals by detecting the characteristics of a paper sheet and a controller 60 for controlling the actuating devices so as to adjust the entry angles automatically in accordance with the sensor output signals for changing the detected characteristics of the paper sheet to desired characteristics.