To provide a method for detecting a methylated DNA, capable of easily detecting the DNA from a slight amount of a cell specimen, by excluding a process for extracting a nucleic acid from a cell in the cell specimen, and to provide a method for utilizing the same.

This method comprises a process of dissolving the cell specimen in a solvent to prepare a cell specimen solution, a process of converting non-methylated cytosine in a base sequence of a CpG-containing DNA which is contained in the cell specimen solution obtained in the dissolving process into uracil by treating the cell specimen solution with a bisulfite salt-containing reagent, a process of amplifying the CpG-containing DNA obtained in the converting process through polymerase chain reaction by using a prescribed methylation-specific oligonucleotide primer, and a process of detecting whether the CpG-containing DNA is amplified or not in the amplifying process. The method simply and rapidly detects methylation of the DNA.