To provide a roller hemming apparatus that prevents dirt and flaws from being generated on a panel to be processed.

The roller hemming apparatus 100 includes a roller 11, a head 12 and a control device. In the roller hemming apparatus, the control device controls the head 12 to be moved along a peripheral edge 1a of an outer panel 1 while pressing a processing surface 11a of the roller 11 onto the peripheral edge 1a of the outer panel 1 to cause the roller 11 to roll on the peripheral edge 1a of the outer panel 1, thereby folding back the peripheral edge 1a of the outer panel 1 to a side of an inner panel 2 and integrally combining the outer panel 1 and the inner panel 2. The roller hemming apparatus includes an impurity removing mechanism 13 having a part that comes into contact with the processing surface 11a and is extended across one side edge to the other side edge relative to the processing surface 11a in a direction of the rotational axis of the roller 11. The part relatively slides with respect to the processing surface 11a to remove impurities adhered to the processing surface of the roller 11 when the roller 11 rolls.