A yarn producing apparatus for producing carbon nanotube yarn by aggregating carbon nanotube fibers, the yarn producing apparatus comprising: a substrate support configured to support a carbon nanotube forming substrate; a continuous drawing unit configured to continuously draw the carbon nanotube fibers from the carbon nanotube forming substrate; a yarn producing unit configured to aggregate the carbon nanotube fibers drawn by the continuous drawing unit; a status monitor configured to monitor a state of the carbon nanotube fibers drawn from the carbon nanotube forming substrate or the carbon nanotube yarn; and a supply state changing mechanism configured to change a supply state of the carbon nanotube fibers drawn from the carbon nanotube forming substrate and supplied to the yarn producing unit, based on a result of monitoring by the status monitor wherein the substrate support includes a plurality of substrate supports, and the supply state changing mechanism changes a supply state of the carbon nanotube fibers by changing the number of carbon nanotube forming substrates from which the carbon nanotube fibers are drawn, characterized in that the supply state changing mechanism includes an initial drawing unit configured to draw the carbon nanotube fibers from the carbon nanotube forming substrate and bring the drawn carbon nanotube fibers into contact with carbon nanotube fibers drawn from another carbon nanotube forming substrate, and a controller configured to control the initial drawing unit such that the carbon nanotube fibers are drawn from the carbon nanotube forming substrate and the drawn carbon nanotube fibers are brought into contact with the carbon nanotube fibers drawn from another carbon nanotube forming substrate when adding the carbon nanotube forming substrate to draw the carbon nanotube fibers. a substrate support configured to support a carbon nanotube forming substrate; a continuous drawing unit configured to continuously draw the carbon nanotube fibers from the carbon nanotube forming substrate; a yarn producing unit configured to aggregate the carbon nanotube fibers drawn by the continuous drawing unit; a status monitor configured to monitor a state of the carbon nanotube fibers drawn from the carbon nanotube forming substrate or the carbon nanotube yarn; and a supply state changing mechanism configured to change a supply state of the carbon nanotube fibers drawn from the carbon nanotube forming substrate and supplied to the yarn producing unit, based on a result of monitoring by the status monitor wherein the substrate support includes a plurality of substrate supports, and the supply state changing mechanism changes a supply state of the carbon nanotube fibers by changing the number of carbon nanotube forming substrates from which the carbon nanotube fibers are drawn, characterized in that the supply state changing mechanism includes an initial drawing unit configured to draw the carbon nanotube fibers from the carbon nanotube forming substrate and bring the drawn carbon nanotube fibers into contact with carbon nanotube fibers drawn from another carbon nanotube forming substrate, and a controller configured to control the initial drawing unit such that the carbon nanotube fibers are drawn from the carbon nanotube forming substrate and the drawn carbon nanotube fibers are brought into contact with the carbon nanotube fibers drawn from another carbon nanotube forming substrate when adding the carbon nanotube forming substrate to draw the carbon nanotube fibers.