To investigate constituents of Lampteromyces japonicus (Kawam.) Singer which grows wildly in Korea, the carpophores of the fungus were collected in Gyeong Gi. Province and analyzed for sterols and amino acids by gas chromatography and an amino acid autoanalyzer. The results showed that it contained stigmasterol and ergosterol and that it contained eleven free amino acids. These free amino acids were also determined quantitatively. Furthermore, sixteen amino acids were identified in the total amino acid fraction of the fruiting body.