Provided is a high voltage wideband pulse attenuator having an attenuation value self-correction function. The high voltage wideband pulse attenuator includes an input unit for receiving a pulse signal, a T-shaped attenuator circuit for attenuating the pulse signal, an output unit for outputting the pulse signal attenuated by the attenuator circuit, and a capacitive divider circuit for dividing a voltage of the pulse signal input through the input unit or the pulse signal attenuated by the attenuator circuit. Using the capacitive divider circuit, the high voltage wideband pulse attenuator can easily measure an error of an attenuation value caused by a change in the resistance of T-shaped array resistor units in a process of attenuating an input pulse signal of tens of kV or more. In particular, the pulse attenuator can measure its performance by itself without test assisting devices, and check a state of an attenuated pulse in real-time.