A power conversion device, comprising: an inverter circuit provided with serial bodies aligned in parallel between a positive and a negative terminals of a DC voltage source and formed of switching elements (5H, 5L) in pairs corresponding to respective phases (U, V, W) of a multiphase AC motor and configured in such a manner that voltages (Vw, Vv, Vu) of the respective phases to drive the motor are extracted from connection points of the switching elements (5H, 5L) in the respective serial bodies; current detection resistors (6u, 6v, 6w) connected between the respective serial bodies and the negative terminal of the DC voltage source; current detection means for detecting a current flowing to the motor for each phase by detecting the potential difference across the terminals of the respective current detection resistors; A/D conversion means provided to the current detection means for performing current value detection processing by converting current detection signals (Iu, Iv, Iw) detected by the current detection means to digital signals (ADIu, ADIv, ADIw); a control unit that outputs drive signals to perform PWM control on the respective switching elements (5H, 5L) of the inverter circuit according to voltage instruction values (Vu*, Vv*, Vw*) of voltages to be applied to the respective phases of the motor or duty ratio setting values; and current detection phase selection means for selecting the current detection signals detected by the respective current detection means and controlling timing of the current detection value detection processing by the A/D conversion means, the power conversion device being characterized in that the current detection phase selection means sets the timing of the current value detection processing by the A/D conversion means within one cycle of a PWM pulse, which is a carrier wave in the PWM control, according to the voltage instruction values or the duty ratio setting values, wherein the current value detection processing of a phase with a third largest voltage instruction value or duty cycle is performed following the current value detection processing of phases with a largest and second largest voltage instruction values or duty cycles. an inverter circuit provided with serial bodies aligned in parallel between a positive and a negative terminals of a DC voltage source and formed of switching elements (5H, 5L) in pairs corresponding to respective phases (U, V, W) of a multiphase AC motor and configured in such a manner that voltages (Vw, Vv, Vu) of the respective phases to drive the motor are extracted from connection points of the switching elements (5H, 5L) in the respective serial bodies; current detection resistors (6u, 6v, 6w) connected between the respective serial bodies and the negative terminal of the DC voltage source; current detection means for detecting a current flowing to the motor for each phase by detecting the potential difference across the terminals of the respective current detection resistors; A/D conversion means provided to the current detection means for performing current value detection processing by converting current detection signals (Iu, Iv, Iw) detected by the current detection means to digital signals (ADIu, ADIv, ADIw); a control unit that outputs drive signals to perform PWM control on the respective switching elements (5H, 5L) of the inverter circuit according to voltage instruction values (Vu*, Vv*, Vw*) of voltages to be applied to the respective phases of the motor or duty ratio setting values; and current detection phase selection means for selecting the current detection signals detected by the respective current detection means and controlling timing of the current detection value detection processing by the A/D conversion means, the power conversion device being characterized in that the current detection phase selection means sets the timing of the current value detection processing by the A/D conversion means within one cycle of a PWM pulse, which is a carrier wave in the PWM control, according to the voltage instruction values or the duty ratio setting values, wherein the current value detection processing of a phase with a third largest voltage instruction value or duty cycle is performed following the current value detection processing of phases with a largest and second largest voltage instruction values or duty cycles.