To provide a technique capable of sufficiently capturing and discharging a vaporized component when melting and kneading the resin by using a raw material containing a lot of vaporized components.

The vaporized component removal device for removing an organic vaporized component generated in kneading the molten resin comprises an inner sidewall (1) of the vaporized component removal device for capturing a condensate of the organic vaporized component and a groove (3) formed by a weir (2) and the angle () between the weir (2) and the inner sidewall (1) of the vaporized component removal device forms an acute angle. The extruder includes the vaporized component removal device, and the method for kneading the resin molten body uses the extruder.