An ultra-high frequency nanometer oscillator belongs to a nanometer oscillator. A fixing end of a carbon nano-tube (1) of the oscillator is fixed and connected with a cathode of a power supply; a free end of the carbon nano-tube (1) is close to a negative electrode (3) which is connected with an anode of the power supply, and the gap is within 10 percent of the length of the carbon nano-tube. When the voltage is applied between the cathode and the anode, a strong electric field is generated between the free end of the carbon nano-tube and the negative electrode; the carbon nano-tube is electrically extended to 10 percent, and the gap between the carbon nano-tube and the negative electrode is decreased until a tunneling current is produced. Therein, the electric field intensity disappears due to the inductance of electric current, the carbon nano-tube retracts under the function of elastic strain energy, the gap between the carbon nano-tube and the negative electrode increases, the tunneling current disappears, the electric field is strengthened correspondingly, and the carbon nano-tube is electrically extended again. The carbon nano-tube experiences electrical extension and elastic retraction alternatively, the frequency increases following the decrease of the length of the carbon nano-tube, which reaches hundreds of GHz to several THz within the length range of nanometer scale. The utility model has a simple structure, which can realize THz controllable oscillation.