Abstract: First and second grippers are moveable in the longitudinal direction along needle beds of the weft knitting machine and in a direction that is closer to and away from a needle bed gap of the needle beds, switchable between a state of not holding a yarn and a state of holding the yarn, and moveable independently of each other. A cutter for cutting the yarn is provided on the first gripper. A control section controls the movements and the switching of the states of the first and second grippers, and the cutter so that in a state where the yarn is held by the first gripper and the second gripper, the held yarn is cut with the cutter. The end yarns generated by cutting the yarn with the cutter are not left in cut state, but treated by the first gripper and the second gripper independently of each other.