An operation torque estimating portion estimates an operation torque Th of a driver based on an input angle .theta.h and an input torque T output from a torque sensor. A non-holding state detecting portion determines whether the driver is holding a steering wheel by comparing an absolute value of the operation torque Th and a predetermined value .epsilon.1. An equilibrium detecting portion determines whether an equilibrium point is reached by comparing the absolute value of the input torque T with a predetermined value .epsilon.2. When it is determined that the driver is not holding the steering wheel and the equilibrium point is reached, a switching portion switches to such a position that causes a target steering adjusting portion to multiply a target output angle .theta. pm by a predetermined gain G according to the input torque T so that the target steering angle is made smaller.