PURPOSE: A unsolidified yarn which has melt spun is rapidly cooled with a specific means to permit the control of the proportion and size of the thick part and produce thick-and-thin yarns with high thick-part proportion in industrial scales.

CONSTITUTION: For example, a cooling liquid such as water is made to flow down through pipe 6 from the gap between cooler 3 and cap 4 over the surface of the cooler 3 and received with tray 5 and expelled from pipe 7. Yarn 2 which has melt extruded from spinning pack 1 is, while unsolidified, passed through the layer of cooling liquid 8 on the surface of the cooler 3, then cooled to solidify outside of the colling liquid layer 8 and taken up. The shape of thick and thin parts, the intervals between thick parts and others can be controlled with the spinning, cooling conditions, for example, the increase in throughput enlarges the size of thick parts and extends the interval between thick parts, while the decrease in take-up speed and drop in cooling temperature increase the size of thick parts and shorten the interval between thick parts.

USE: Woven or knitted fabrics with unique touch, filter and filler.