A failure determination device for a rotating machine control device, the failure determination device comprising: a power converter configured to supply power to a rotating machine; a current detector configured to detect a rotating machine current to be supplied to the rotating machine; a first angle sensor configured to generate at least two electrical signals in accordance with a rotation angle of the rotating machine; a first sine wave signal output device configured to output a first sine wave signal and a second sine wave signal based on the at least two electrical signals generated by the first angle sensor; a first angle calculator configured to output a first angle detection value based on the first sine wave signal and the second sine wave signal; a second angle sensor configured to generate at least two electrical signals in accordance with the rotation angle of the rotating machine; a second sine wave signal output device configured to output a third sine wave signal and a fourth sine wave signal based on the at least two electrical signals generated by the second angle sensor; a second angle calculator configured to output a second angle detection value based on the third sine wave signal and the fourth sine wave signal; a rotation angle estimator configured to output a rotation angle estimation value with respect to the rotation angle of the rotating machine based on the rotating machine current, which is detected by said current detector; and an angle sensor failure determiner (15a-15e) configured to detect failure of the first angle sensor and the second angle sensor, the angle sensor failure determiner (15a-15e) being configured to determine the failure of the first angle sensor or the second angle sensor based on at least two of: a difference between the rotation angle estimation value and the first angle detection value; a difference between the rotation angle estimation value and the second angle detection value; and a difference between the first angle detection value and the second angle detection value. a power converter configured to supply power to a rotating machine; a current detector configured to detect a rotating machine current to be supplied to the rotating machine; a first angle sensor configured to generate at least two electrical signals in accordance with a rotation angle of the rotating machine; a first sine wave signal output device configured to output a first sine wave signal and a second sine wave signal based on the at least two electrical signals generated by the first angle sensor; a first angle calculator configured to output a first angle detection value based on the first sine wave signal and the second sine wave signal; a second angle sensor configured to generate at least two electrical signals in accordance with the rotation angle of the rotating machine; a second sine wave signal output device configured to output a third sine wave signal and a fourth sine wave signal based on the at least two electrical signals generated by the second angle sensor; a second angle calculator configured to output a second angle detection value based on the third sine wave signal and the fourth sine wave signal; a rotation angle estimator configured to output a rotation angle estimation value with respect to the rotation angle of the rotating machine based on the rotating machine current, which is detected by said current detector; and an angle sensor failure determiner (15a-15e) configured to detect failure of the first angle sensor and the second angle sensor, the angle sensor failure determiner (15a-15e) being configured to determine the failure of the first angle sensor or the second angle sensor based on at least two of: a difference between the rotation angle estimation value and the first angle detection value; a difference between the rotation angle estimation value and the second angle detection value; and a difference between the first angle detection value and the second angle detection value. a difference between the rotation angle estimation value and the first angle detection value; a difference between the rotation angle estimation value and the second angle detection value; and a difference between the first angle detection value and the second angle detection value.