To provide an electronic control device of a rear wheel steering mechanism capable of surely correcting the detecting voltage with the inexpensive constitution even if a temperature drift is caused in a sensor for detecting an actual steering angle of rear wheels.

This electronic control device 10 is provided with a target steering angle setting means 20 for setting rear wheel steering information S1 on the basis of front wheel steering of a front wheel steering control system 190 of an automobile, a steering direction indicating means 30 for indicating the steering direction Dr of rear wheels 161, 162 to electromagnetic actuators 141, 142, and a steering angle adjusting means 40 for supplying a driving current IM to an electric motor 120 according to a target steering angle θr of the rear wheels 161, 162 and adjusting a steering angle of the rear wheels 161, 162, and is also juxtaposed with an actual steering angle measuring means 50 for measuring an actual steering angle θR of the rear wheels 161, 162 being steered, and a correction commanding means 60 for sending out a correction command S3 to the actual steering angle measuring means 50 when a mechanism part exists in a neutral position or a maximum steering angle position while watching an overcurrent signal S2 in the steering angle adjusting means 40.