To find out a use and a product which can effectively utilize a synergistic action caused by the characteristics of a biodegradable plastic and tourmaline, respectively.

A mixture obtained by mixing and dispersing the tourmaline with the biodegradable plastic is used and molded into compost bags, food trays or flower pots. Thereby, the actions of the tourmaline on organisms can be used, and the degradation of the mixture with microorganisms can be promoted, after used. Further, the action of the tourmaline on soil can be utilized, also after the mixture is degraded.