PURPOSE: To obtain a cotton comber sufficiently durable even to high-speed revolution, by using a pair of mutually engaged noncircular gears fixed to a cylinder shaft and a nipper shaft respectively and having outer contours shaped to particular forms.

CONSTITUTION: Noncircular gears 12, 13 are fixed to a cylinder shaft 10 and a nipper shaft 11 respectively and the nipper shaft 11 is oscillated by the mutual engagement of the gears. In a cotton comber having the above construction, the contours of the noncircular gears 12, 13 are made in the following manner. The angular velocity ratio - displacement curve between two noncircular gears has tow peaks and valleys having different heights. The angular velocity ratio at the higher peak is ≤1.9 and that at the deeper valley is ≥0.53.