amplification measuring apparatus is provided with a measuring part for measuring a nucleic acid amplification product obtained by amplifying the mrna of cytokeratin 19 in a detection sample with primers and a nucleic acid amplification enzyme in an embodiment of the present invention the judging means is not particularly limited insofar as the presence or absence of lymph node metastasis of stomach cancer can be absolutely or relatively judged on the basis of the quantitative value of the mrna of cytokeratin 19 quantified by the quantification means described above the judging means is preferably a means of judging cancer metastasis by comparing the quantitative value with a predetermined threshold value the quantitative value is particularly preferably the absolute value of the mrna of cytokeratin 19 in a detection sample the apparatus therefor may be provided with a display for displaying the obtained judgment results in an embodiment of the present invention the apparatus comprises a means for obtaining an indicator for judging the level of metastasis of a metastatic focus in a lymph node tissue the means for obtaining an indicator may be a means other than the cancer metastasis judging means or may be integrated into one means having both the functions an embodiment.