Electron energy loss spectroscopy (EELS) and electron spectroscopic imaging techniques are applied to a carbon nanotube (NT) to reveal the fine electronic state in the cylindrical structure of graphite. Although NTs with large diameters show similar EELS patterns at the carbon K-edge (285 eV) to those of graphite, a fine molecular straw with a diameter less than 5 nm exhibits different features. Especially it was found that the angular-resolved EELS formed by electrons scattered normal to the longitudinal axis of the NT indicates a strong contribution of tau* excitation compared with sigma* excitation. It confirms that the anisotropy of the NT exists in the structure and electronic structure.