A reel attaching/detaching device that attaches/detaches a reel on which a tape accommodating a component is wound to and from a feeder which feeds out the tape by a drive of a feed-out section and supplies the component, the device includes a feeder set unit configured to be set in a predetermined orientation when the feeder supplies the component, a reel set unit configured to be set in a predetermined orientation when the reel supplies the component, a transfer robot configured to transfer the reel between the feeder set unit and the reel set unit while holding a orientation of the reel, and a control device configured to control the transfer robot so that the reel is detached from the reel set unit and the reel is attached to the feeder set in the feeder set unit, when the reel is set in the reel set unit.