A yarn winder comprising: a bobbin holder which extends in a predetermined direction, bobbins on which yarns are wound, respectively, being attached to the bobbin holder to be lined up in the predetermined direction; traverse guides which are provided above the bobbin holder and traverses the yarns; and a guide unit which is provided above the traverse guides and includes fulcrum guides and a guide supporter, the fulcrum guides being lined up in the predetermined direction and functioning as fulcrums of traversal of the yarns, and the guide supporter extending in the predetermined direction and supporting the fulcrum guides, the fulcrum guides being gatherable to an end portion of the guide supporter, the end portion being on one side in the predetermined direction, the guide unit being movable between a yarn winding position where the yarns are wound onto the respective bobbins and a yarn threading position which is at least on the one side in the predetermined direction of the yarn winding position, wherein, the yarn threading position is on the one side in the predetermined direction of and above the yarn winding position, the yarn winder further comprising: a frame which extends in the predetermined direction along the guide unit and supports the guide unit to be movable in a relative manner in the predetermined direction; and a head portion which is attached to an end portion of the frame, the end portion being on the one side in the predetermined direction, characterized in that no matter whether the guide unit is at the yarn winding position or at the yarn threading position, an end portion of the guide unit, which is on the one side in the predetermined direction, is on the other side in the predetermined direction of the end portion of the head portion, which is on the one side in the predetermined direction. a bobbin holder which extends in a predetermined direction, bobbins on which yarns are wound, respectively, being attached to the bobbin holder to be lined up in the predetermined direction; traverse guides which are provided above the bobbin holder and traverses the yarns; and a guide unit which is provided above the traverse guides and includes fulcrum guides and a guide supporter, the fulcrum guides being lined up in the predetermined direction and functioning as fulcrums of traversal of the yarns, and the guide supporter extending in the predetermined direction and supporting the fulcrum guides, the fulcrum guides being gatherable to an end portion of the guide supporter, the end portion being on one side in the predetermined direction, the guide unit being movable between a yarn winding position where the yarns are wound onto the respective bobbins and a yarn threading position which is at least on the one side in the predetermined direction of the yarn winding position, wherein, the yarn threading position is on the one side in the predetermined direction of and above the yarn winding position, the yarn winder further comprising: a frame which extends in the predetermined direction along the guide unit and supports the guide unit to be movable in a relative manner in the predetermined direction; and a head portion which is attached to an end portion of the frame, the end portion being on the one side in the predetermined direction, a frame which extends in the predetermined direction along the guide unit and supports the guide unit to be movable in a relative manner in the predetermined direction; and a head portion which is attached to an end portion of the frame, the end portion being on the one side in the predetermined direction, characterized in that no matter whether the guide unit is at the yarn winding position or at the yarn threading position, an end portion of the guide unit, which is on the one side in the predetermined direction, is on the other side in the predetermined direction of the end portion of the head portion, which is on the one side in the predetermined direction.