To enable an efficient and sure cleaning of a roller capable of cleaning off a treatment liquid from a peripheral surface of the roller by a small amount of a cleaning liquid.

A cleaning trough 110 provided oppositely to the roller 56A of conveying roller pair 56 is disposed along a horizontal direction parallel to an axis of the roller. A groove 118 of the trough 114 is provided in a substantially V shape by a bottom plate 120 and a side plate 122, a through hole 126 is formed at the side plate at the intermediate part, a through hole 128 is formed at the bottom 124 out of the hole 126, and a bottom 124A of a distal end is inclined toward the peripheral surface of the roller. The cleaning water supplied from a nozzle 116 disposed at the intermediate position of the longitudinal direction is dispersed to the holes 126 and 128 and both ends and flowed to the peripheral surface of the roller 56. Thus, the conveying roller pair can be surely cleaned without using a large quantity of the water.