To provide a biodegradable paper product, especially a paper product which is decayed to produce an organic manure after used and scrapped and can thereby be degraded in the natural environment without needing removal.

This biodegradable corrugated base paper contains a photosynthetic bacterium group grown by assimilating inorganic nutrients or organic nutrients with or without light energy. The corrugated board box is produced from the corrugated base paper. Since the paper material contains the photosynthesis bacterium group, the paper material can biologically be degraded, or the period of the biodegradation can be shortened. Especially, the paper material has a remarkable effect, when applied to a paper product, such as a corrugated board box, which contains pulp or the like as a raw material, is degraded in the natural environment in a certain extent after scrapped, is slowly (biologically) degraded because of being relatively thick or the like, and therefore needs many days until the paper material is degraded and decayed with bacteria in soil to return to the soil. Thereby, the incineration of such the paper products, such as corrugated paper, as incinerated in large amounts can be avoided, and evils such as considerations on waste treatments and the damages of incinerators can be removed.