Abstract: The present invention relates to a hog ring clamping device such as a C ring clamping device. In the hog ring clamping device of the invention, a knock pin is mounted to a movable member of a jaw driving unit, a pivotable member is mounted to a hog ring clamping device body, the pivotable member is pushed against the knock pin by means of spring, a feed member is mounted to the pivotable member so that it can come into contact with hog rings engaged with a magazine, and a presser wheel is mounted to the hog ring clamping device body through a unidirectional rotating unit so as to be in contact with the hog rings engaged with the magazine.