An automatic yarn threading device configured to perform yarn threading onto a yarn processing apparatus, comprising: a yarn threading arm; a storage unit which is configured to store arm movement information regarding how the yarn threading arm is moved when the yarn threading arm is caused to perform the yarn threading onto the yarn processing apparatus at a predetermined reference position; and a controller, characterized in that the storage unit is further configured to store information of an actual position of the yarn processing apparatus, and when the yarn threading arm is caused to perform the yarn threading onto the yarn processing apparatus, the controller moving the yarn threading arm based on the arm movement information which is corrected based on a difference between the actual position of the yarn processing apparatus and the reference position, the automatic yarn threading device being further configured to perform the yarn threading onto plural yarn processing apparatuses each of which is identical with the yarn processing apparatus, wherein, the storage unit is configured to store the arm movement information regarding how the yarn threading arm is moved when the yarn threading arm is caused to perform the yarn threading onto a first yarn processing apparatus among the yarn processing apparatuses and information of an actual position of each of the yarn processing apparatuses, and when the yarn threading arm is caused to perform the yarn threading onto a second yarn processing apparatus which is different from the first yarn processing apparatus among the yarn processing apparatuses, the controller moving the yarn threading arm based on the arm movement information which is corrected based on a difference between the position of the first yarn processing apparatus and the position of the second yarn processing apparatus. a yarn threading arm; a storage unit which is configured to store arm movement information regarding how the yarn threading arm is moved when the yarn threading arm is caused to perform the yarn threading onto the yarn processing apparatus at a predetermined reference position; and a controller, characterized in that the storage unit is further configured to store information of an actual position of the yarn processing apparatus, and when the yarn threading arm is caused to perform the yarn threading onto the yarn processing apparatus, the controller moving the yarn threading arm based on the arm movement information which is corrected based on a difference between the actual position of the yarn processing apparatus and the reference position, the automatic yarn threading device being further configured to perform the yarn threading onto plural yarn processing apparatuses each of which is identical with the yarn processing apparatus, wherein, the storage unit is configured to store the arm movement information regarding how the yarn threading arm is moved when the yarn threading arm is caused to perform the yarn threading onto a first yarn processing apparatus among the yarn processing apparatuses and information of an actual position of each of the yarn processing apparatuses, and when the yarn threading arm is caused to perform the yarn threading onto a second yarn processing apparatus which is different from the first yarn processing apparatus among the yarn processing apparatuses, the controller moving the yarn threading arm based on the arm movement information which is corrected based on a difference between the position of the first yarn processing apparatus and the position of the second yarn processing apparatus.