In the process of producing a porous body containing a fibrous apatite/collagen composite by gelating a dispersion comprising said fibrous apatite/collagen composite, collagen and water, freeze-drying the resultant gel to form a porous body, and cross-linking collagen in said porous body, a method for controlling the average pore diameter of said porous body by the solidification time of said gel in said freezing step.
