To facilitate the installing work of a roll body.

The supporting device for a roll body is a guide part formed by projecting from either one side of a supporting shaft and the roll body, and it includes a guide part having a guide surface opposing to the other side of the supporting shaft and the roll body in the up and down direction. The above guide surface is abutted to the above other side at the position coinsiding the supporting shaft and the axial core of the roll body, in the condition that the supporting member is at the waiting position, and the device is formed to maintain this abutting condition until the supporting member and the roll body are made in the fitting condition by the movement of the supporting member.