A viscous medium feeder, which has an inlet, an outlet, a tubular portion, a rotatable cylindrical shaft arranged in and extending coaxially with the tubular portion, and a drive motor connected to the shaft. The tubular portion has an internal thread, which is connected, at one end thereof, to the inlet, and, at the other end thereof, to the outlet. Further, the tubular portion is elastic, and the shaft abuts the inner wall portions of the tubular portion.