The flavor concentrate obtained by the extraction of “Katsuobushi” of bonito (Katsuwonus pelamis) with 80% ethanol and by the subsequent steam distillation of the extract was fractionated by the usual method and the resulting neutral, non-carbonyl oxygenated fraction was investigated by gas chromatography. The following components were tentatively identified: 2-pentanol and 2-methyl-l-heptanol as free alcohols, and 4 alcohos of n- and isobutanol, n-pentanol and n-dodecanoll and 9 carboxylic acids of propanoic, n-butanoic, n-pentanoic, n-octanoic, n-nonanoic n-decanoic, n-dodecanoic, n-tetradecanoic and n-hexadecanoic acid as the constituents of esters. A constituent alcohol existing in the largest amount was isolated by gas chromatography and identified as 2-methyl-l-heptanol by elemental analysis, NMR, IR, and MS. A constituent acid existing in large amount was also isolated and investigated similarly, and the structure was partially estimated. 2-Methyl-l-heptanol holds a fresh woody aroma and seems to have a major effect on “Katsuobushi” flavor.