An electric power steering apparatus that driving-controls a three-phase brushless motor which applies an assist torque to a steering mechanism of a vehicle by using a current command value calculated based on at least a steering torque, and vector-controls said three-phase brushless motor by using dq-axes command values that are converted from said current command value via an inverter , characterized in that said electric power steering apparatus comprising: a three-phase disturbance observer to compensate respective phase disturbance voltages, which include a dead time of said inverter , for 3-phase voltage command values, wherein said 3-phase disturbance observer includes phase observer sections comprising a motor model , an inverse motor model and a low pass filter for each of three phases, and wherein said phase observer sections comprise: a first subtracting section to subtract a disturbance estimation voltage from a phase voltage that is converted into three phases; a gain section to multiply a subtraction value from said first subtracting section by a gain; said motor model to input a phase voltage that adds a disturbance element to an output of said gain section , and to output a phase current; said inverse motor model to input said phase current; said low pass filter to input said subtraction value; and a second subtracting section to subtract an output of said low pass filter from an output of said inverse motor model , and to output said disturbance estimation voltage. a three-phase disturbance observer to compensate respective phase disturbance voltages, which include a dead time of said inverter , for 3-phase voltage command values, wherein said 3-phase disturbance observer includes phase observer sections comprising a motor model , an inverse motor model and a low pass filter for each of three phases, and wherein said phase observer sections comprise: a first subtracting section to subtract a disturbance estimation voltage from a phase voltage that is converted into three phases; a gain section to multiply a subtraction value from said first subtracting section by a gain; said motor model to input a phase voltage that adds a disturbance element to an output of said gain section , and to output a phase current; said inverse motor model to input said phase current; said low pass filter to input said subtraction value; and a second subtracting section to subtract an output of said low pass filter from an output of said inverse motor model , and to output said disturbance estimation voltage. a first subtracting section to subtract a disturbance estimation voltage from a phase voltage that is converted into three phases; a gain section to multiply a subtraction value from said first subtracting section by a gain; said motor model to input a phase voltage that adds a disturbance element to an output of said gain section , and to output a phase current; said inverse motor model to input said phase current; said low pass filter to input said subtraction value; and a second subtracting section to subtract an output of said low pass filter from an output of said inverse motor model , and to output said disturbance estimation voltage. <EOS>