[Problem]An object of the present invention is to provide an electric power steering apparatus that has a 3-shunt control function to perform a 3-shunt PWM-control for raising a reliability of the apparatus and for improving a stability, and a 1-shunt control function to perform a 1-shunt PWM-control so as to continue an assist control when the 3-shunt control function is damaged.[Means for solving the problem]The electric power steering apparatus according to the present invention, having: a 3-shunt control function to perform a 3-shunt PWM-control with a first 3-phase detected current values based on down-stream 3-shunt; a 1-shunt control function to perform a 1-shunt PWM-control with a second 3-phase detected current values based on down-stream 1-shunt; and a switching function to switch from the 3-shunt control function to the 1-shunt function when a failure of current detection circuit system in relation to the first 3-phase detected current values is detected.