An apparatus for packing articles in which said articles are fed in a continuous flow in equally spaced apart relation and wrapped continuously by a web of packing material, comprising means for wrapping said material around the articles, means for forming a longitudinal sealing seam and driving the wrap formed around the articles with a predetermined velocity and means for forming a transverse sealing seam between the articles and for severing it, constituted by at least two rollers mounted for rotation and provided with at last one sealing jaw, the rollers being in driving connection with each other and one of the rollers being connected to a driving shaft of the packing apparatus through a mechanism by which mechanism the rollers are rotated with a non-constant rotational velocity, which mechanism comprises a crank arm (1) connected, for a rotational movement around a shaft extending perpendicular to the arm, to a coupling member (4) mounted for rotation around a shaft extending in spaced relation parallel to the rotational shaft of the crank arm and connected with the driving shaft, while at the crank arm a driving cam (11) is provided which is received shiftable in a slot (12) formed in a follower member (13) extending parallel to the crank arm and fixed to a shaft (15) which is in driving connection with a sealing roller, the axis of said shaft extending perpendicular to the follower member in spaced apart relation with the driving cam, while said slot extends in radial direction with respect to said axis and the crank arm is provided with means by which every time the axis of rotation of the crank arm has moved along a complete circular path said arm is rotated at least one time over 360° around said axis.