A power conversion apparatus of an electric vehicle includes: a power converter for driving an induction machine based on arbitrary d- and q-axis voltage commands Vd* and Vq*, and a control unit for controlling the power converter based on a power running command P and a brake command B from outside. The control unit includes: a dq/three-phase conversion unit for converting phase current information iu, iv, and iw detected from the induction machine into d- and q-axis current detection values id and iq on orthogonal rotating coordinates; a speed determination unit for computing d- and q-axis voltage commands Vd* and Vq* for the power converter and determines that speed of the induction machine is zero based on the power running command P, the brake command B, and the d- and q-axis current detection values id and iq; and a resistance computing unit for computing a resistance value of the induction machine based on the power running command P, the d-axis current detection value id, and the d-axis voltage command Vd* when the brake command B is changed to the power running command P and the speed determination unit determines that the speed of the induction machine is zero.