A method for diagnosing cancer, comprises detecting volatile organic compounds (VOCs) contained specifically in exhaled breath of cancer patients, and more particularly, to a method for providing information for cancer diagnosis, which comprises a step of measuring whether ionized fragments of cancer-specific VOCs, which have molecular weights of (i) 69, (ii) 131 and (iii) 181, are present in exhaled breath gas collected from patients suspected of having cancer. Cancer can be early diagnosed with high sensitivity in a non-invasive manner by use of exhaled breath sampled from cancer patients. Thus, the cancer diagnosis method can diagnose cancer in a more cost-effective and rapid manner compared to conventional cancer diagnosis methods.
