An additional type reel holding device configured to be attached to a component supply device provided on a component mounter, the component supply device including multiple feeder devices and a standard reel holding section configured to hold multiple tape reels in a rotatable and exchangeable manner. The additional type reel holding device is attached as an addition to the standard reel holding section, holds additional tape reels different to the tape reels held by the standard reel holding section in a rotatable and exchangeable manner, and supplies the carrier tapes wound on the additional tape reels to the feeder devices. Thus, it is possible to increase the overall quantity of carrier tapes supplied to feeder devices from the standard reel holding section and the additional type reel holding device.