We present a simple method to determine the nature of single wall nanotubes (SWNTs) in a bundle prepared by chemical vapor deposition technique by resonant Raman spectroscopy. The sample is irradiated with two wavelengths 633nm from He-Ne laser and 514.5nm from Ar⁺ laser. The spectra were taken in backscattering geometry and theoretical calculation has been carried out at one peak position 216cm^-1 in RBM spectra. The results reveal that one third of the carbon nanotubes are metallic in agreement with the previously proposed reports. The geometrical and electronic properties of nanotubes are also discussed.