A substrate-cleaning apparatus may include a tilting arm to which a roll brush and a motor are coupled, a support arm positioned on the tilting arm, a first spring and a second spring coupling the tilting arm to the support arm, a first air bag and a second air bag mounted between the tilting arm and the support arm, and a controller configured to adjust an internal pressure of each of the first air bag and the second air bag. The controller may adjust a difference in internal pressure between the first air bag and the second air bag to control the inclination of the roll brush, and may adjust the internal pressure of each of the first air bag and the second air bag to move the roll brush vertically.