Disclosed is as a biomarker useful in early diagnosis of lung cancer, at least one protein selected from the group including Quescin-sulfhydryl oxidase 1, Fibrillin-1, Isoform A of Lamin-A / C, Latent-transforming growth factor beta-binding protein 2, Galectin-1, highly similar to Dickkopf-related protein 3, Isoform A1-B of Heterogeneous nuclear ribonucleoprotein A1, 14-3-3 protein epsilon, Stanniocalcin-2, Cystatin-C, Isoform 1 of Connective tissue growth factor, Profilin-1, Isoform 1 of Extracellular matrix protein 1, Histone H2B type 2-E, Kinesin-like protein KIF26A, Zinc finger protein 516, and Isoform 1 of A-kinase anchor protein 9.