A rotary electric machine controller including a current detector detecting rotary electric machine currents generated in a rotary electric machine, a position estimation mechanism outputting an estimated position in accordance with the rotary electric machine currents; a controller outputting voltage commands in accordance with the estimated position; a pulse-width modulator outputting logic signals which are pulse-width modulated in accordance with the voltage commands and with a switching cycle used for pulse-width modulation control; and a voltage application mechanism applying AC voltages for driving the rotary electric machine in accordance with the logic signals. The voltage commands output by the controller are obtained by superimposing, on fundamental voltages for driving the rotary electric machine, position detection voltages which each have a cycle equal to m times of the switching cycle and which are different in phase among respective phases.