PURPOSE: To suppress the flocculation of a developer by housing a bag body into a container body and packing the developer into this bag body.

CONSTITUTION: The bag body 20 is provided in the container body 10 and the developer is housed into this bag body. Some air layer exists between the bag body 20 housing the developer and the container body 10. This air layer acts as a heating insulating layer. A non-woven fabric which does not allow the leakage of the developer and has air permeability is used for the bag body 20 and the fabric which is formed to a bag shape opened in the upper part is used. The transfer of heat to the developer housed in the bag body 20 is, therefore, lessened even if the heat is applied to the container body 10 housing the bag body 20. The flocculation of the developer is thus suppressed.