A method for producing a plurality of DNA probes comprising steps of: conducting a nucleic acid amplification reaction in a reaction solution containing genomic DNA and random primers having 9-30 bases using genomic DNA as a template to obtain DNA fragments, wherein when the random primers comprise 9 to 10 bases, the concentration of the random primers is 40 to 60 microM; when the random primers comprise 10 to 14 bases, the concentration of the random primers satisfy the conditions defined by an inequation: y > 3E + 08x -6.974 and be 100 microM or less, provided that the base lengths of the random primers are represented by "y" and the concentration of the random primers is represented by "x"; when the random primers comprise 14 to 18 bases, the concentration of the random primers is 4 to 100 microM; when the random primers comprise 18 to 28 bases, the concentration of such random primers be 4 microM or more and satisfy the conditions defined by an inequation: y < 8E + 08x -5.533; when the random primers comprise 28 to 29 bases, the concentration of the random primers is 6 to 10 microM; when the random primers comprise 30 bases, the concentration of the random primers is 6 microM; determining the nucleotide sequences of the obtained DNA fragments; and designing a plurality of DNA probes used for detecting DNA fragments obtained in the above step on the basis of the nucleotide sequences of the DNA fragments by identifying a region or a plurality of regions of the base lengths shorter than those of the DNA fragments and covering at least a part of the DNA fragments, wherein the DNA probes comprise nucleotide sequences complementary to the identified one or more regions. conducting a nucleic acid amplification reaction in a reaction solution containing genomic DNA and random primers having 9-30 bases using genomic DNA as a template to obtain DNA fragments, wherein when the random primers comprise 9 to 10 bases, the concentration of the random primers is 40 to 60 microM; when the random primers comprise 10 to 14 bases, the concentration of the random primers satisfy the conditions defined by an inequation: y > 3E + 08x -6.974 and be 100 microM or less, provided that the base lengths of the random primers are represented by "y" and the concentration of the random primers is represented by "x"; when the random primers comprise 14 to 18 bases, the concentration of the random primers is 4 to 100 microM; when the random primers comprise 18 to 28 bases, the concentration of such random primers be 4 microM or more and satisfy the conditions defined by an inequation: y < 8E + 08x -5.533; when the random primers comprise 28 to 29 bases, the concentration of the random primers is 6 to 10 microM; when the random primers comprise 30 bases, the concentration of the random primers is 6 microM; determining the nucleotide sequences of the obtained DNA fragments; and designing a plurality of DNA probes used for detecting DNA fragments obtained in the above step on the basis of the nucleotide sequences of the DNA fragments by identifying a region or a plurality of regions of the base lengths shorter than those of the DNA fragments and covering at least a part of the DNA fragments, wherein the DNA probes comprise nucleotide sequences complementary to the identified one or more regions.