PURPOSE: To enable the burying of a plurality of bone reservoirs into a very limited land by molding a container and a lid forming the bone reservoir using organic material digestable and decomposable by small living creatures and microorganisms in soil as derived from plants.

CONSTITUTION: This bone reservoir, for example, has a cylindrical container 1 20cm across and 20cm high and a lid 2. The container and the lid are molded with an organic material derived from plants, for example, beat, leaf mold and straw decayed and are produced at a very low cost. As to a method of entombing the bone reservoir, for example, a chamber 5 having an operable door 4 is arranged in contact with the rear of a memorial stone 3 indicating group entombing and a hole 7 is made into the soil from the surface 6 of the ground in the chamber. Then, the bone reservoirs 1 and 2 are inserted until it reaches the bottom of the hole 7. The bone reservoirs 1 and 2 are dixested by small living creatures in the soil, for example, earth worm, wood louse and millipede and also decomposed by microorganisms and are mostly changed to carbon dioxide, water and ammonia while the rest thereof is transformed to humus as brown black amorphous organic matter. The bone ashes in the bone reservoirs are also decomposed by phosphorus dissolving bacteria or the like and changed to phosphate component to be absorbed by roots of plants.