PURPOSE: To set a steering angle detecting value to an approximate actual steering angle during steering of a handle at a high speed by a method wherein in a region where a steering angular velocity exceeds a read limit speed, a correction steering angle is cumulatively added in a given ratio to a pulse count value at a point of time when the steering angular velocity attains a read limit speed.

CONSTITUTION: During steering of a handle, in a region where a steering angular velocity is below a read limit speed, the number of pulses of a pulse signal responding to a handle steering angle from a handle steering angle sensor (a) is counted by a handle steering angle detecting value computing means 6, and the pulse count value is set to a handle steering detecting value as it is. When a steering speed by a steering angular velocity computing means (c) to compute the change speed of a handle steering angular velocity exceeds a read limit speed, a value obtained by cumulatively adding in a given ratio a correction steering angle value to a pulse count value at a point of time when a steering angular velocity attains a read limit speed is set as a handle steering angular velocity detecting value in a region exceeding a limit speed.