To prevent an article to be packed from losing its freshness even in a state housed in a packing bag for a long period of time by using a carbon- containing packing material mixed with fine granular carbon.

At first, a vinyl raw material 1a and fine granular carbon 1b produced by processing charcoal into fine particles are charged in a mixing tank 1 to be sirred and mixed over a predetermined time and the obtained carbon mixed raw material 2 is charged in a receiving tank 3 and heated to obtain a liquid raw material 3a which is, in turn, sent into a cylinder 5 by a screw 4 to be sent to a blower 8 through a sending pipe 7 and blown up from the blower 8 by air pressure sent through air ducts 9, 9 by a compressor 6 to produce a packing material 10 mixed with fine granular carbon. Even if an article to be packed is housed in this bag for a long period of time, it does not lose its freshness.