Abstract: A case top folder and flap supporter is disclosed having a pair of folding arms each disposed at one side and near the top of the case and mounted for pivotal movement from a vertical position to a horizontal position over the case so as to urge a pre-glued first set of flaps into a closed position spanning the top of the case. Fixed at the end of each such folding arm is an engaging means comprising in one form a depending hook-like projection with a concavity, and in another form a sawtooth edge, each of which is operable to engage the outer edge of a flap while such flap is being folded to the closed position. In the flap closed position the folding arms support the first flap set by maintaining engagement with the flap outer edges so that a second flap folding assembly, which comprises a pair of pre-break folding arms and a platen, can descend from above the case to fold the second flap set over and press the same into contact with the supported first flaps until the glue is set.