A rotation angle detection device detecting a rotation angle of a rotating body and comprising: a first sensor disposed at a first position at a periphery of the rotating body and outputting a first sinusoidal signal in accordance with a rotation of the rotating body; a second sensor disposed at a second position at the periphery of the rotating body and at an angular interval from the first position and outputting a second sinusoidal signal, having a positional phase difference corresponding to the angular interval from the first sinusoidal signal, in accordance with the rotation of the rotating body; and a rotation angle computing device (20, 40, 60) computing the rotation angle based on the first sinusoidal signal and the second sinusoidal signal, wherein the rotation angle computing device (20, 40, 60) comprises: a signal correction unit (22, 41, 61) correcting one sinusoidal signal of the first sinusoidal signal and the second sinusoidal signal so that the positional phase difference that is a phase difference between the signals is made equal to a target phase difference; a rotation angle computing unit (23, 42, 62) computing the rotation angle based on the one sinusoidal signal corrected by the signal correction unit and the other sinusoidal signal; characterized in that, the rotation angle computing device (20, 40, 60) further comprises: a first signal abnormality judging unit judging whether or not the first sinusoidal signal is abnormal based on the one sinusoidal signal corrected by the signal correcting unit and the second sinusoidal signal; and a second signal abnormality judging unit judging whether or not the second sinusoidal signal is abnormal based on the one sinusoidal signal corrected by the signal correcting unit and the first sinusoidal signal. a first sensor disposed at a first position at a periphery of the rotating body and outputting a first sinusoidal signal in accordance with a rotation of the rotating body; a second sensor disposed at a second position at the periphery of the rotating body and at an angular interval from the first position and outputting a second sinusoidal signal, having a positional phase difference corresponding to the angular interval from the first sinusoidal signal, in accordance with the rotation of the rotating body; and a rotation angle computing device (20, 40, 60) computing the rotation angle based on the first sinusoidal signal and the second sinusoidal signal, wherein the rotation angle computing device (20, 40, 60) comprises: a signal correction unit (22, 41, 61) correcting one sinusoidal signal of the first sinusoidal signal and the second sinusoidal signal so that the positional phase difference that is a phase difference between the signals is made equal to a target phase difference; a rotation angle computing unit (23, 42, 62) computing the rotation angle based on the one sinusoidal signal corrected by the signal correction unit and the other sinusoidal signal; a signal correction unit (22, 41, 61) correcting one sinusoidal signal of the first sinusoidal signal and the second sinusoidal signal so that the positional phase difference that is a phase difference between the signals is made equal to a target phase difference; a rotation angle computing unit (23, 42, 62) computing the rotation angle based on the one sinusoidal signal corrected by the signal correction unit and the other sinusoidal signal; characterized in that, the rotation angle computing device (20, 40, 60) further comprises: a first signal abnormality judging unit judging whether or not the first sinusoidal signal is abnormal based on the one sinusoidal signal corrected by the signal correcting unit and the second sinusoidal signal; and a second signal abnormality judging unit judging whether or not the second sinusoidal signal is abnormal based on the one sinusoidal signal corrected by the signal correcting unit and the first sinusoidal signal. a first signal abnormality judging unit judging whether or not the first sinusoidal signal is abnormal based on the one sinusoidal signal corrected by the signal correcting unit and the second sinusoidal signal; and a second signal abnormality judging unit judging whether or not the second sinusoidal signal is abnormal based on the one sinusoidal signal corrected by the signal correcting unit and the first sinusoidal signal.