We developed a conductance measurement system of a single carbon fullerene simultaneously with a transmission electron microscope (TEM) observation. A single carbon fullerene was made from an agglomerate of carbon atoms suspended between both gold electrodes. When the bias voltage above 0.6 V was applied between both electrodes, the transformation into a single carbon fullerene was observed. We measured electrical conductance of the single carbon fullerene adsorbed on the electrode surface in the process of bringing the opposite side electrode close to it. The conductance showed tunneling behavior from 10⁻⁵ to 10⁻² G₀ (= 2e²/h ; quantized unit of conductance) and abruptly jumped to 0.5 G₀. TEM observation showed that an ellipsoidal carbon fullerene expanded along the normal direction to the electrode surface and had a contact with the electrode, which corresponded to the conductance jump. The conductance value of the fullerene was 0.5-0.6 G₀.