In a voltage detection device for a transforming apparatus, a voltage divider is constituted by providing an intermediate electrode between a central conductor and a tank of the transforming apparatus, to detect a voltage E1 of the central conductor based on a voltage E2 of the voltage divider. The voltage detection device for a transforming apparatus includes an incomplete integration circuit having a reverse characteristic to an input/output voltage amplitude ratio-frequency characteristic of a high-pass filter formed by a floating electrostatic capacitance between the central conductor and the intermediate electrode, an earth electrostatic capacitance between the intermediate electrode and the tank, and a voltage dividing resistor connected in parallel to the earth electrostatic capacitance, and a signal processing circuit that outputs a value based on an output voltage E3 of the incomplete integration circuit as the voltage E1 of the central conductor.