3C--SiC nanowhisker and a method of synthesizing 3C--SiC nanowhisker wherein its diameter and length can be controlled. The method is safe and low cost, and the whisker can emit visible light of various wavelengths. 3C--SiC nanowhisker is formed by depositing thin film (2) made of a metal element on Si substrate (1), placing this Si substrate (1) into a plasma CVD apparatus, and holding it for predetermined time at predetermined substrate temperature in the plasma consisting of hydrogen and hydrocarbon. Si of Si substrate (1) and C in plasma dissolve at supersaturation into metal liquid particle (3), 3C--SiC nanowhisker (4) grows on the metal liquid particles (3), whisker surface is terminated with H so as to maintain the diameter constant, and the metal liquid particles (3) at whisker root take in Si from Si substrate (1) and penetrate into Si substrate (1).