This invention provides: a pluripotent cell derived from a non-human animal comprising foreign DNA that encodes a desired protein in such a manner that the expression of the desired protein is regulated by the control region of a gene expressed in certain cells and/or tissue, wherein the foreign DNA is bound to a nucleic acid fragment comprising a promoter/the whole or part of 5' non-translational region/a leader sequence coding region derived from a gene expressed in certain cells and/or tissue, and wherein in said cell one or more drug resistant marker genes used for introducing the foreign DNA into the genome have been removed; a chimeric non-human animal that is prepared from the pluripotent cell and highly expresses the desired protein, or a progeny thereof; a method for producing a desired protein using the chimeric animal; and a method for analyzing in vivo function of a desired gene using the chimeric animal.