The impulse generator comprises a nonlinear transmission line capable of obtaining an impulse with a small half value width and a large amplitude, in which a plurality of transmission line units having a unit line unit and a diode are connected in series, a pulse generator connected to the transmission terminal of the nonlinear transmission line, and a bias-dependent element connected to the reception terminal of the nonlinear line, wherein the anode of the diode of the transmission line unit is connected to the transmission line and the cathode is connected to the ground, and one end of the bias-dependent element is connected to the reception terminal of the transmission line and the other end is biased to a negative potential.