A blanket-mounting mechanism includes a dragging shaft, a rotating device, a correction device, and a deflection suppression device. A dragging-shaft accommodation bore extends axially through a blanket cylinder. A blanket insertion groove extends axially on the outer circumferential surface of the blanket cylinder and extends radially to the dragging-shaft accommodation bore. The dragging shaft has a blanket-end reception groove formed on the outer circumferential surface and adapted to receive one end of a blanket. The dragging shaft is inserted into the dragging-shaft accommodation bore with an appropriate gap maintained therebetween and is supported rotatably. The rotating device is disposed at the side of one end face of the blanket cylinder and is connected to the dragging shaft. The correction device is disposed at the side of the other end face of the blanket cylinder and is able to grip/release the dragging shaft so as to adjust the angular position of the dragging shaft. The deflection suppression device supports the dragging shaft accommodated within the dragging-shaft accommodation bore while permitting the dragging shaft to rotate.