We have developed a well controlled method for manipulating carbon nanotubes. The firstcrucial process involved is to prepare a nanotube array, named a nanotube cartridge. Wehave discovered ac electrophoresis of nanotubes by which nanotubes are aligned atthe knife-edge. The nanotubes used were multiwalled and prepared by an arcdischarge with a relatively high gas temperature. The second important process is totransfer a nanotube from the nanotube cartridge onto a substrate in a scanningelectron microscope (SEM). Using this method, we have developed nanotubetips and nanotube tweezers that operate in a scanning probe microscope (SPM).The nanotube probes have been applied for the observation of biological samplesand industrial samples to clarify their advantages. The nanotube tweezers havedemonstrated their motion in an SEM and have operated to carry nanomaterials in aSPM.We have also developed the electron ablation of a nanotube to adjust its length and thesharpening of a multiwall nanotube to have its inner layer with or without an end cap atthe tip. For the sharpening process, the free end of a nanotube protruding from thecartridge was attached to a metal-coated Si tip and a voltage was applied to the nanotube.When a high voltage was used in the saturation current regime, the current decreasedstepwise in the temporal variation, indicating the sequential destruction of individualnanotube layers. The nanotube was finally cut at the middle of the nanotube bridge, andits tip was sharpened to have an inner layer with an opened end. Moving up thecartridge before cutting enables us to extract the inner layer with an end cap.It is evidenced that the maximum current in each layer during the stepwise decreasedepends on its circumference, and the force for extracting the inner layer with ~5 nm diameter is ~4 nN.