Abstract: The object of the present invention is to provide a gene amplification method, wherein the method can amplify both methylated and unmethylated nucleic acids present in a biological sample, and further regulate the amplification ratio of the methylated and/or unmethylated nucleic acid as needed. Such objects can be solved by an amplification method using a nonspecific primer which can hybridize both with methylated and unmethylated nucleic acids and a specific primer which specifically hybridizes with either methylated or unmethylated nucleic acid, and further by an amplification method which can change the amplification ratio of methylated or unmethylated nucleic acid by changing the mixing rate of these primers.