Abstract: A rotary blow molding machine includes a rotor mounted on a horizontal driving shaft, a recovery hopper, an ejector mechanism, and mold stations mounted on the outer periphery of the rotor, which mold stations are radially disposed and circumferentially equally spaced, the mold stations each carrying thereon a split mold unit capable of opening and closing in the direction of the width of the outer peripheral surface of the rotor by a mold opening/closing mechanism, a mold clamping mechanism and a flash blow-pipe, the said split mold unit having a mold-release mechanism. It is so constructed as to produce blow moldings successively continuously at high speed and completely automatically during a single rotation of the mold stations on and along the same circular rotation track.