A coil manufacturing apparatus for forming a helical structure by connecting together a plurality of strip-shaped flat conductors (C1, C2) capable of having a helical shape when continuously joined together, the coil manufacturing apparatus comprising: a first holding part and a second holding part capable of sandwiching one of the flat conductors and a different one of the flat conductors, respectively, and disposed opposite to each other; movement restraining unit configured to bias the flat conductor and the different flat conductor in a direction, in which they come close each other at least in a retracted state; a biasing member configured to bias the first holding part and the second holding part in a direction in which they are separated away from each other; a fixing member configured to hold the flat conductor and the different flat conductor at predetermined positions in the first direction in the retracted state; an interference avoidance space for accommodating part of the flat conductor on a front side in a helical traveling direction of the helical structure; and a drive part for moving the first holding part and the second holding part, wherein the first holding part and the second holding part are means configured to form the helical structure by: setting a prepared length, corresponding to a total distance of the plurality of strip-shaped flat conductors (C1, C2) in a strip longitudinal direction, to be longer than a finished length of the helical structure to be finally obtained in a helical longitudinal direction by a margin; pressing end faces of the plurality of strip-shaped flat conductors (C1, C2) against each other along the strip longitudinal direction and thus shortening distances thereof in the strip longitudinal direction to cold pressure weld the end faces together; and setting a total shortened distance, corresponding to an amount shortened by the cold pressure welding of all of the plurality of strip-shaped flat conductors (C1, C2), to the margin. a first holding part and a second holding part capable of sandwiching one of the flat conductors and a different one of the flat conductors, respectively, and disposed opposite to each other; movement restraining unit configured to bias the flat conductor and the different flat conductor in a direction, in which they come close each other at least in a retracted state; a biasing member configured to bias the first holding part and the second holding part in a direction in which they are separated away from each other; a fixing member configured to hold the flat conductor and the different flat conductor at predetermined positions in the first direction in the retracted state; an interference avoidance space for accommodating part of the flat conductor on a front side in a helical traveling direction of the helical structure; and a drive part for moving the first holding part and the second holding part, wherein the first holding part and the second holding part are means configured to form the helical structure by: setting a prepared length, corresponding to a total distance of the plurality of strip-shaped flat conductors (C1, C2) in a strip longitudinal direction, to be longer than a finished length of the helical structure to be finally obtained in a helical longitudinal direction by a margin; pressing end faces of the plurality of strip-shaped flat conductors (C1, C2) against each other along the strip longitudinal direction and thus shortening distances thereof in the strip longitudinal direction to cold pressure weld the end faces together; and setting a total shortened distance, corresponding to an amount shortened by the cold pressure welding of all of the plurality of strip-shaped flat conductors (C1, C2), to the margin. setting a prepared length, corresponding to a total distance of the plurality of strip-shaped flat conductors (C1, C2) in a strip longitudinal direction, to be longer than a finished length of the helical structure to be finally obtained in a helical longitudinal direction by a margin; pressing end faces of the plurality of strip-shaped flat conductors (C1, C2) against each other along the strip longitudinal direction and thus shortening distances thereof in the strip longitudinal direction to cold pressure weld the end faces together; and setting a total shortened distance, corresponding to an amount shortened by the cold pressure welding of all of the plurality of strip-shaped flat conductors (C1, C2), to the margin.