The transient phenomenon of chip generations and behavior in the gear hobbing process are investigated by using a high-speed video camera. The chip behavior generated in gear finish hobbing process is very complicated and one can not identify each chip from specified cutting edges. The authors have built up a new simulation method of the hobbing process using a flying tool and a special-shaped workpiece, which consists of one tooth space. Visual evidences of the chip interference on the rake face and some conditions of contact between generated chips and the work surface were visually obtained. In the case of dry cutting conditon with a high-speed steel (HSS) flytool without coating on the rake face, the flytool cuts the workpiece frequently with the stuck chip generated in the previous revolution on the rake face. The newly generated chip pushes out the previous stuck chip, which flies away eventually. The chip flow on the rake face interferes strongly at the corner of the cutting edge when both top and side cutting edges produce different chips at the same time, and the chips flow out in changing the shape. The moving speed of the chip was also measured.