A hemming apparatus (1) includes a holder unit (2), a lower die (3) on which the holder unit (2) is installed, and an upper die (4) which is installed on the lower die (3) vertically movably. The holder unit (2) includes a base (5) secured to the lower die (3) by means of bolts or the like; a working tool holder (7) which is rotatably supported on the base (5) so that a hemming punch (6) can be disposed at a nonworking position and a working position; and a resilient means (8) for resiliently urging the working tool holder (7) so as to dispose the hemming punch (6) at the nonworking position.