An objective is to provide a specific realization means for easily determining malfunction of a system in an electromotive power steering controller. The electromotive power steering controller includes: a voltage controller for controlling voltage applying to a motor based on a d-axis current command value and a q-axis current command value that are set by a d-q-command-value setting unit, and a d-axis current detection value and a q-axis current detection value that are obtained by, using the d-q coordinate system, transforming three-phase ac current that has been actually flowing in the motor and has been detected by a current detector; and a malfunction determining unit for determining that malfunction has occurred in the control system if at least one of the phase-current detection value is out of a first predetermined permissible range.