Abstract: A hole-punching assembly comprising a positioning piece, a clamping piece, a plurality of tool holders, two balancing rods and a plurality of hole mountings. Each end of the positioning piece couples to the hole mounting through a balancing rod, the positioning piece has a gliding rail, a receiving slot and a confining part disposed at an indentation at each end for each of the tool holders to go through the positioning piece, thereby fixing the tool holders. Each of the tool holders has a first end extending to one of the hole mountings and a second end being blocked by the clamping piece. The clamping piece has one rod disposed at each end, with each end of the rod protruding through the receiving slot axially and being restrained by the confining part, thereby fixing the clamping piece and forcing the tool holder to move axially to facilitate easy switching and dismantling of the tool holders.