Thin carbon nanocoil (CNC) with a fiber diameter of less than 50 nm was synthesized by catalytic chemical vapor deposition using Fe-Sn catalyst supported on zeolite. The chemical vapor deposition parameters of reaction temperature, gas flow rate of N2 as dilute gas and C2H2 as source gas were 650-750 degrees C, 1000 ml/min and 50-300 ml/min respectively. Transmission electron microscopic observation revealed that thin CNCs had a hollow and multi-walled structure with cylindrical graphitic layers. More than 90% of the CNCs obtained were multi-walled CNCs (MWCNCs), and the remainder was columnar CNCs without a hollow structure. Three-dimensional images of an MWCNC with Au nanoparticles on its surface were reconstructed by electron tomography and confirmed that the MWCNC had a three-dimensional helical shape.