Provided is a robot cleaner wherein a driving structure is optimized since a motor and an axis rotated by the motor are directly connected by a universal joint. The robot cleaner comprises: a main body including an inlet; a brush unit placed on the inlet to be able to rotate; and a driving device to drive the main body. The brush unit comprises: a main brush mounted on the inlet; a main brush motor to produce a rotary force for rotating the main brush; a rotary axis to rotate the main brush by receiving the rotary force of the main brush motor by being combined to the main brush; and the universal joint to make the rotary force of the main brush motor to be transferred to the rotary axis since the rotary axis and motor axis of the main brush motor are directly connected.
