PURPOSE: To improve the efficacy of a granular chemical and prevent the chemical from peeling and falling off due to external force such as abrasive or vibrating force by a method wherein the granular chemical is spread over a sheet of paper with desired seal part left and is buried and fixed by a synthetic resin layer having a barrier property against the chemical by means of extrusion coating.

CONSTITUTION: A sheet of paper 1 is transferred at a desired speed to a conveyer 4, and a required amount of a chemical 2 is spread over the paper 1 from a hopper so as to leave desired seal parts, or the chemical 2 is spread by a comb teeth 5 so as to leave the desired seal parts 9. Then, molten resin 3 delivered from an extruder is laminated by a guide roller 6. Then, the resin is pressed by pinch rollers 7 to bury and fix the chemical 2, and at the same time, the paper 1 and the molten resin 3 are pressed and stuck together at the seal parts, so that the synthetic resin, the chemical and the paper are united into a packaging material 8.