We prepared a transgene comprising human HB-EGF precursor cDNA, as a diphtheria toxin receptor gene, at the downstream of an insulin promoter, and introduced this transgene into a mouse fertilized egg, to produce a transgenic mouse of the present invention. In this mouse, human HB-EGF precursors are expressed specifically in islet beta cells, and by injection of diphtheria toxin, islet beta cells are selectively destroyed, resulting in that the mouse shows diabetes two or three days after the injection. This mouse can be utilized in screening and development of new medicines and therapy protocols for diabetes.