Disclosed is a method of collecting cells including the steps of: preparing a processed-bone comprising a bone extracted from a living body, a covering agent and first and second holes, wherein an outer surface of the bone is covered with the covering agent attached to the outer surface of the bone, and the first and second holes penetrate through the covering agent and the outer surface of the bone into the interior of the bone introducing a liquid into the processed-bone from the first hole and collecting a cell-containing liquid from the second hole.
