To provide a conveying device an object to be treated and a decoration method for an object to be treated using the device capable of performing surface treatment of a plurality of objects to be treated in a state where they are mounted to a lengthy article through a spindle while performing encircling action or the like of the lengthy article together with a lengthy truck.

The object to be treated conveying device is provided with the lengthy article having a spindle for mounting the object to be treated; the lengthy truck removably engaging the lengthy article; and a movement means for moving the lengthy truck. A plurality of joining positions are provided between the lengthy truck and the movement means and a variable member for changing a distance between the plurality of joining positions accompanying with non-linear advancement of the lengthy truck is provided.