An AC motor drive controller, comprising: an AC motor; an inverter; and an overmodulation PWM controller which controls a pulse width modulation voltage which is output from the inverter and which is to be applied to the AC motor, based on a result of comparison between a phase voltage instruction ( vu, vv, vw) in which an amplitude exceeds a peak value of a triangular wave carrier and the triangular wave carrier, wherein the overmodulation PWM controller includes: a voltage instruction calculation unit which calculates a d-axis voltage instruction ( vd) and a q-axis voltage instruction ( vq) such that a d-axis current and a q-axis current which are detected correspond to the d-axis current instruction and the q-axis current instruction; and a voltage amplitude calculator which calculates a voltage instruction amplitude from the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) calculated by the voltage instruction calculation unit; characterized in that the overmodulation PWM controller further includes a voltage instruction correction unit which corrects the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) calculated by the voltage instruction calculation unit, such that a pulse width modulation voltage has a fundamental wave amplitude corresponding to the voltage instruction amplitude calculated by the voltage amplitude calculator; a voltage instruction conversion unit which converts the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) which are corrected into a phase voltage instruction ( vu, vv, vw) and outputs the phase voltage instruction ( vu, vv, vw); and a synchronization PWM controller which controls a phase of the phase voltage instruction ( vu, vv, vw) from the voltage instruction conversion unit and the triangular wave carrier, and wherein the voltage instruction correction unit corrects the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) calculated by the voltage instruction calculation unit in accordance with the synchronization number which is the number of the triangular wave carriers per one cycle of the phase voltage instruction ( vu, vv, vw). an AC motor; an inverter; and an overmodulation PWM controller which controls a pulse width modulation voltage which is output from the inverter and which is to be applied to the AC motor, based on a result of comparison between a phase voltage instruction ( vu, vv, vw) in which an amplitude exceeds a peak value of a triangular wave carrier and the triangular wave carrier, wherein the overmodulation PWM controller includes: a voltage instruction calculation unit which calculates a d-axis voltage instruction ( vd) and a q-axis voltage instruction ( vq) such that a d-axis current and a q-axis current which are detected correspond to the d-axis current instruction and the q-axis current instruction; and a voltage amplitude calculator which calculates a voltage instruction amplitude from the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) calculated by the voltage instruction calculation unit; a voltage instruction calculation unit which calculates a d-axis voltage instruction ( vd) and a q-axis voltage instruction ( vq) such that a d-axis current and a q-axis current which are detected correspond to the d-axis current instruction and the q-axis current instruction; and a voltage amplitude calculator which calculates a voltage instruction amplitude from the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) calculated by the voltage instruction calculation unit; characterized in that the overmodulation PWM controller further includes a voltage instruction correction unit which corrects the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) calculated by the voltage instruction calculation unit, such that a pulse width modulation voltage has a fundamental wave amplitude corresponding to the voltage instruction amplitude calculated by the voltage amplitude calculator; a voltage instruction conversion unit which converts the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) which are corrected into a phase voltage instruction ( vu, vv, vw) and outputs the phase voltage instruction ( vu, vv, vw); and a synchronization PWM controller which controls a phase of the phase voltage instruction ( vu, vv, vw) from the voltage instruction conversion unit and the triangular wave carrier, and a voltage instruction correction unit which corrects the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) calculated by the voltage instruction calculation unit, such that a pulse width modulation voltage has a fundamental wave amplitude corresponding to the voltage instruction amplitude calculated by the voltage amplitude calculator; a voltage instruction conversion unit which converts the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) which are corrected into a phase voltage instruction ( vu, vv, vw) and outputs the phase voltage instruction ( vu, vv, vw); and a synchronization PWM controller which controls a phase of the phase voltage instruction ( vu, vv, vw) from the voltage instruction conversion unit and the triangular wave carrier, and wherein the voltage instruction correction unit corrects the d-axis voltage instruction ( vd) and the q-axis voltage instruction ( vq) calculated by the voltage instruction calculation unit in accordance with the synchronization number which is the number of the triangular wave carriers per one cycle of the phase voltage instruction ( vu, vv, vw).