A yarn winding machine (1, 1A) for winding a yarn to form a package, comprising: a winding mechanism which winds the yarn; and a traverse mechanism (4, 4A) which traverses the wound yarn, wherein the traverse mechanism (4, 4A) includes: a drive unit which generates a rotation of a drive shaft, a crank portion which converts the rotation of the drive shaft of the drive unit into a rotation of a circular orbit, and a rotary reciprocating conversion portion which converts the rotation of the circular orbit of the crank portion into a reciprocating motion, wherein the crank portion includes: a first power transmission portion which rotates while being connected to the drive shaft and transmits power of the drive unit, and a second power transmission portion which transmits power to the rotary reciprocating conversion portion, wherein a distance between a rotation axis (Ax) of the first power transmission portion and the second power transmission portion is changeable, and wherein the rotary reciprocating conversion portion includes a traverse guide locking the yarn, wherein the yarn winding machine (1, 1A) further comprises a changing device which changes a distance between the rotation axis (Ax) of the first power transmission portion and the second power transmission portion, characterized in that the yarn winding machine (1, 1A) further comprises a control device which is a processor provided with an integrated circuit or a computer system equipped with said processor and controls an operation of the changing device, so that a traverse width is changed at a desired timing. a winding mechanism which winds the yarn; and a traverse mechanism (4, 4A) which traverses the wound yarn, wherein the traverse mechanism (4, 4A) includes: a drive unit which generates a rotation of a drive shaft, a crank portion which converts the rotation of the drive shaft of the drive unit into a rotation of a circular orbit, and a rotary reciprocating conversion portion which converts the rotation of the circular orbit of the crank portion into a reciprocating motion, a drive unit which generates a rotation of a drive shaft, a crank portion which converts the rotation of the drive shaft of the drive unit into a rotation of a circular orbit, and a rotary reciprocating conversion portion which converts the rotation of the circular orbit of the crank portion into a reciprocating motion, wherein the crank portion includes: a first power transmission portion which rotates while being connected to the drive shaft and transmits power of the drive unit, and a second power transmission portion which transmits power to the rotary reciprocating conversion portion, a first power transmission portion which rotates while being connected to the drive shaft and transmits power of the drive unit, and a second power transmission portion which transmits power to the rotary reciprocating conversion portion, wherein a distance between a rotation axis (Ax) of the first power transmission portion and the second power transmission portion is changeable, and wherein the rotary reciprocating conversion portion includes a traverse guide locking the yarn, wherein the yarn winding machine (1, 1A) further comprises a changing device which changes a distance between the rotation axis (Ax) of the first power transmission portion and the second power transmission portion, characterized in that the yarn winding machine (1, 1A) further comprises a control device which is a processor provided with an integrated circuit or a computer system equipped with said processor and controls an operation of the changing device, so that a traverse width is changed at a desired timing.