Abstract: A flap-folding device for use in a packaging machine comprises a rotational disc, drive means for rotating the disc in synchronization with movement of a blank and articles to be packaged in the blank, a pair of blank-engaging fingers pivotally mounted on the disc to fold flaps on the blank, and actuating means for pivotally moving the fingers. The actuating means comprises a radial member mounted on the disc for reciprocating movement along the radius of the disc, cooperating means for moving the radial member along the radius in response to rotation of the disc, and means for converting reciprocating movement of the radial member into pivotal movement of the fingers.