TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Property: The pour point of bio-diesel oil is 15 to -24degreesC, preferably -12 to -21degreesC. Preferred Composition: The bio-diesel oil contains 10 mass% or less of saturated methyl ester and/or ethyl ester, and 90 mass% or more of 18:1C or 18:2C unsaturated methyl ester and/or ethyl ester. The sum total content of saturated methyl ester and/or ethyl ester derived from mixture (M) containing palm oil, palm kernel, oil, palm oil product and/or palm kernel oil product is 7 mass% or less. The sum total content of 18:1C methyl ester and/or ethyl ester in palm oil and palm kernel oil is 70 mass% or more. The saturated methyl or ethyl ester is 14C methyl or ethyl ester, 16C methyl or ethyl ester and/or 18C methyl or ethyl ester.Preferred Compounds: The bio-diesel oil contains methyl ester of myristic acid, palmitic acid, oleic acid or linoleic acid.Preferred Oil: The bio-diesel oil has pour point of -20degreesC, when the oil contains methyl ester of myristic acid (in mass%) (0.5), methyl ester of palmitic acid (4.9), methyl ester of oleic acid (83.6) and methyl ester of linoleic acid (11). The bio-diesel oil has pour point of -15degreesC, when the oil contains methyl ester of myristic acid (0.6), methyl ester of palmitic acid (5.7), methyl ester of oleic acid (79), methyl ester of stearic acid (2) and methyl ester of linoleic acid (12.7). The bio-diesel oil has pour point of -12degreesC, when the oil contains methyl ester of myristic acid (0.6), methyl ester of palmitic acid (6.3), methyl ester of oleic acid (74.6), methyl ester of stearic acid (2.9) and methyl ester of linoleic acid (15.7). The bio-diesel oil has pour point of -9degreesC, when the oil contains methyl ester of myristic acid (0.7), methyl ester of palmitic acid (6.7), methyl ester of oleic acid (75.5), methyl ester of stearic acid (0.4) and methyl ester of linoleic acid (16.7). The bio-diesel oil has pour point of -33degreesC, when the oil contains methyl ester of myristic acid (1.6), methyl ester of palmitic acid (5), methyl ester of oleic acid (72.9), methyl ester of stearic acid (0.7), methyl ester of arachic acid (0.4) and methyl ester of linoleic acid (19.4).Preferred Conditions: The esterification process during manufacture of bio-diesel oil is carried out in the presence of liquid or solid form acidic catalyst (0.5-1), at 110-160degreesC. Fractional distillation performed during manufacture of bio-diesel oil, is carried out at 5-30 Pa.Preferred Method: The crystallization process required during manufacture of bio-diesel oil is performed by dry-type classification or solvent separation, preferably solvent separation. Palm oil and palm-kernel oil containing methyl ester and/or ethyl ester, are manufactured by esterification using methanol and/or ethanol. The esterification is carried out at 60-65degreesC for 45 minutes to 1 hour, in the presence of alkali catalyst (0.25-1).Preferred Catalyst: The acidic catalyst is concentrated sulfuric acid, concentrated hydrochloric acid, sulfonic aid and/or solid acid catalyst. The alkali catalyst is sodium hydroxide, sodium methoxide and/or potassium hydroxide.Preferred Solvent: The solvent required during solvent separation process is methanol, ethanol and/or isopropanol. EXAMPLE - Oleic acid having purity of 80% was esterified with methanol in the presence of acidic catalyst. A mixture of methyl ester of myristic acid (in mass%) (0.5), methyl ester of palmitic acid (4.9), methyl ester of oleic acid (83.6) and methyl ester of linoleic acid (11) was obtained. The obtained methyl ester mixture had pour point of -21degreesC. Hence a bio-diesel oil was produced. The obtained oil had favorable fuel characteristics such as viscosity, flash point, sulfur content, carbon residue, specific gravity, combustion heat amount and boiling point, and had improved flow characteristics at low temperature.