All independent elastic moduli of unidirectional carbon-epoxy composites were measured in the tensile and torsional tests of co-axis and off-axis specimens. The experiments were motivated to estimate the unmeasurable elastic moduli of carbon fiber itself. The experimental results were incorporated with the Authors' preceding analytical results which describe the relationships between the moduli of composites and constituents. According to several results, the fact that the hexagonal array packing is more favorable as an idealized model was obtained. It should be noted that carbon fiber is highly anisotropic and that the estimated values of those moduli are reasonable in comparison with those in a few existing references. Some of the basic assumptions employed in the analysis were confirmed by the observation of the transverse and longitudinal sections of the specimens through an electron-scanning-beam microscope (ESM).