PURPOSE: To perform quantitative packaging of small size products with a thermoplastic film at a low cost and with energy saving by a method wherein feeding, measuring, sealing and conveying of the small size products are automatically, continuously carried out with a relatively simple constitution.

CONSTITUTION: Products are dropped one by one into a hopper 1 from the top of a conveyer 2. Polyethylene film as a packaging material are formed into a bag-like shape with an opening under the hopper 1 by a pair of film rolls 3. The two films after bag-shaped are sent to vertical left and right heating bars 5 and welded together. A motor is operated to send the films by a specified length corresponding to the products by a timer. The number of the products which are dropped from the hopper 1 and packaged by the bag-shaped films is counted by a counter, and when the count reaches a specified number of pulse signals, the upper parts of the bag-shaped films are cut off, welded and sealed by a horizontal cutter-heater 7 to complete packaging of the products. At the same time, the ends of the films above the cut part are welded and sealed for the succeeding packaging operation.