Salivary biomarker characterized as low-molecular-weight compounds named metabolites or combinations these biomarkers are used for detecting cancers. As an example of a combination, creatinine, N1-acetylspermidine, α-aminoadipic acid, N-acetylneuraminic acid, and 1,3-diaminopropane is used. The use combination of these markers or single marker enable the early detection of pancreatic cancers, breast cancers, and oral cancers from a healthy subject regardness unstable concentration fluctuations of saliva.