The present invention is intended to discriminate between a battery voltage sensor and the input voltage sensor of a converter for abnormality, without stopping the step-up operation of the converter. A voltage conversion device is provided with a battery, a converter, a battery voltage sensor, a voltage sensor for detecting the input voltage of the converter, a current sensor for detecting a reactor current, and a control unit. The control unit determines the abnormality of the battery voltage sensor or the input voltage sensor on the basis of an estimated value of input voltage calculated based on the reactor current, the input voltage of the converter and a battery voltage, without stopping the step-up operation of the converter.