A synchronous motor control device for an electric vehicle is provided which is able to reduce torque ripple through simple calculation and is excellent in practicability. In a synchronous motor control device (1) which controls a traction synchronous motor (2), torque ripple compensation unit (3) is provided which adds, to a motor drive current, a sine-wave correction current whose phase is opposite to that of torque ripple which is generated in the motor (2) and has a frequency which is six times that of a rotation speed of the motor (2). Specifically, in the case of a configuration including a vector control type basic controller (9), the torque ripple compensation unit (3) outputs a correction current command iq_c, and a value iq_ref obtained by adding the correction current command iq_c to a q-axis current command is used for control.