To provide a winding unit capable of easily reproducing a positional relation before detachment when a bobbin holding device is attached again even in the case that the bobbin holding device is detached for maintenance work or the like.

A reference plate 141 is attached to the constituent member (specifically, a first frame member 151) of a base frame being a member for supporting the downstream-side unit of a winder unit. The reference plate 141 is constituted to be switchable between an adjustable state that it is movable relative to the first frame member 151 and a fixed state where it is immovable relative to the first frame member 151 by loosening or fastening a fastening bolt 161. The bobbin holding device 10 can be attached to and detached from the reference plate 141. When the bobbin holding device 10 is attached to the reference plate 141, it is fixed to the reference plate 141 to be positioned at only one location with respect to the reference plate 141.