There is disclosed herein, a container fitment applicator adaptable to applying a flanged pour spout fitment through an opening in a carton top panel while the carton is on a mandrel of a forming, filling and sealing machine. The applicator includes a rotatable shaft having a bar secured thereto, a vacuum cup or location spigot mounted on one end of the bar, and a roller mounted on the other end of the bar, with a chute and feeder coordinating the supplying of one fitment at a time to the vacuum cup. In one embodiment, the roller engages a first cam which serves to pivot the bar to position the fitment in the center portion of the mandrel to permit loading the carton onto the mandrel, with the fitment entering the panel opening as the roller leaves the cam under the force of a spring operatively connected to the bar. In a second embodiment, a spring positions the bar and fitment in the center portion of the mandrel for the carton loading, and a second cam engaged by the roller serves to extend the fitment into the panel opening. The flange of the fitment is sealed by an ultrasonic sealer and horn to the inner surface of the top panel around the opening while the second cam backs up the roller.