A yarn monitoring device comprising: a sensor adapted to monitor a yarn that is being wound by a yarn winding machine; a determining section adapted to perform a determination based on first information acquired from the sensor and second information acquired from a status acquiring section of the yarn winding machine, and to output a control signal based on the determination; and a cutter adapted to cut the yarn, wherein the determining section is adapted to output as the control signal a signal that causes the cutter to operate and cut the yarn, wherein the second information acquired by the determining section includes a traverse position of the yarn, characterized in that the status acquiring section comprises a yarn detection sensor adapted to output a first yarn detection signal when the yarn crosses a detection area of the yarn detection sensor toward a traverse edge in a traverse stroke of the yarn and to output a second yarn detection signal when the yarn crosses the detection area of the yarn detection sensor toward a traverse center in the traverse stroke of the yarn, wherein the determining section is adapted to output the control signal when the first information indicates that the yarn has a defect and upon receiving the second yarn detection signal. a sensor adapted to monitor a yarn that is being wound by a yarn winding machine; a determining section adapted to perform a determination based on first information acquired from the sensor and second information acquired from a status acquiring section of the yarn winding machine, and to output a control signal based on the determination; and a cutter adapted to cut the yarn, wherein the determining section is adapted to output as the control signal a signal that causes the cutter to operate and cut the yarn, wherein the second information acquired by the determining section includes a traverse position of the yarn, characterized in that the status acquiring section comprises a yarn detection sensor adapted to output a first yarn detection signal when the yarn crosses a detection area of the yarn detection sensor toward a traverse edge in a traverse stroke of the yarn and to output a second yarn detection signal when the yarn crosses the detection area of the yarn detection sensor toward a traverse center in the traverse stroke of the yarn, wherein the determining section is adapted to output the control signal when the first information indicates that the yarn has a defect and upon receiving the second yarn detection signal. wherein the second information acquired by the determining section includes a traverse position of the yarn, characterized in that the status acquiring section comprises a yarn detection sensor adapted to output a first yarn detection signal when the yarn crosses a detection area of the yarn detection sensor toward a traverse edge in a traverse stroke of the yarn and to output a second yarn detection signal when the yarn crosses the detection area of the yarn detection sensor toward a traverse center in the traverse stroke of the yarn, wherein the determining section is adapted to output the control signal when the first information indicates that the yarn has a defect and upon receiving the second yarn detection signal.