An electric power steering apparatus comprising: a torque sensor that detects steering torque exerted on a steering system of a vehicle by a driver of the vehicle and then outputs a torque signal; a motor that is coupled with the steering system, generates assist torque for assisting steering by the driver, and then exerts the assist torque on the steering system; and a control means that drives the motor in such a way that the assist torque corresponding to the torque signal is generated, wherein the control means includes at least a first-stage phase compensation means that is formed of software and applies phase compensation to the torque signal outputted from the torque sensor, a second-stage phase compensation means that is formed of software and applies phase compensation to a torque signal to which phase compensation has been applied by the first-stage phase compensation means, and a third-stage phase compensation means that is formed of software and applies phase compensation to a torque signal to which phase compensation has been applied by the second-stage phase compensation means, characterised by letting T1 and T2 denote time constants, a transfer function of the first-stage phase compensation means is given by a Laplace transformation equation (1 + T1·s)/(1 + T2·s), wherein letting T3 and T4 denote time constants, a transfer function of the second-stage phase compensation means is given by a Laplace transformation equation (1 + T3·s)/(1 + T4·s), wherein letting T5 and T6 denote time constants, a transfer function of the third-stage phase compensation means is given by a Laplace transformation equation (1 + T5·s)/(1 + T6·s), wherein the first-stage phase compensation means, the second-stage phase compensation means, and the third-stage phase compensation means are configured in such a way that a frequency at which a phase calculated through the transfer function of the first-stage phase compensation means becomes maximal and a frequency at which a phase calculated through a transfer function of the second-stage phase compensation means and the third-stage phase compensation means becomes maximal coincide with each other, and wherein the control means controls the motor, based on a torque signal to which the first-stage phase compensation means, the second-stage phase compensation means, and the third-stage phase compensation means have applied phase compensation. a torque sensor that detects steering torque exerted on a steering system of a vehicle by a driver of the vehicle and then outputs a torque signal; a motor that is coupled with the steering system, generates assist torque for assisting steering by the driver, and then exerts the assist torque on the steering system; and a control means that drives the motor in such a way that the assist torque corresponding to the torque signal is generated, wherein the control means includes at least a first-stage phase compensation means that is formed of software and applies phase compensation to the torque signal outputted from the torque sensor, a second-stage phase compensation means that is formed of software and applies phase compensation to a torque signal to which phase compensation has been applied by the first-stage phase compensation means, and a third-stage phase compensation means that is formed of software and applies phase compensation to a torque signal to which phase compensation has been applied by the second-stage phase compensation means, characterised by a first-stage phase compensation means that is formed of software and applies phase compensation to the torque signal outputted from the torque sensor, a second-stage phase compensation means that is formed of software and applies phase compensation to a torque signal to which phase compensation has been applied by the first-stage phase compensation means, and a third-stage phase compensation means that is formed of software and applies phase compensation to a torque signal to which phase compensation has been applied by the second-stage phase compensation means, characterised by letting T1 and T2 denote time constants, a transfer function of the first-stage phase compensation means is given by a Laplace transformation equation (1 + T1·s)/(1 + T2·s), wherein letting T3 and T4 denote time constants, a transfer function of the second-stage phase compensation means is given by a Laplace transformation equation (1 + T3·s)/(1 + T4·s), wherein letting T5 and T6 denote time constants, a transfer function of the third-stage phase compensation means is given by a Laplace transformation equation (1 + T5·s)/(1 + T6·s), wherein the first-stage phase compensation means, the second-stage phase compensation means, and the third-stage phase compensation means are configured in such a way that a frequency at which a phase calculated through the transfer function of the first-stage phase compensation means becomes maximal and a frequency at which a phase calculated through a transfer function of the second-stage phase compensation means and the third-stage phase compensation means becomes maximal coincide with each other, and wherein the control means controls the motor, based on a torque signal to which the first-stage phase compensation means, the second-stage phase compensation means, and the third-stage phase compensation means have applied phase compensation.