A robot cleaner includes: a cleaner body; a driving unit configured to provide a driving force; a driving pulley connected to the driving unit, and formed to be rotatable by receiving the driving force from the driving unit; first and second driven pulleys disposed at both sides of the driving pulley; and a belt forming a closed loop by entirely enclosing the driving pulley and the first and second driven pulleys, and configured to rotate the first and second driven pulleys when the driving pulley is rotated.