To provide a steering control preventing steering vibration generated due to excessive long control cycle when switching from steer-by-wire control (SBW) to power steering type mechanical steering control (EPS).

When the control cycle of the EPS control having a short demand control cycle is equated to a long demand control cycle (5 msec) of the SBW control, the EPS control is started on a longer cycle than the demand control cycle upon transition from the SBW control to the EPS control. Consequently, the time "lag" between the completion of a certain control task and the transition to the next control task is increased, causing the steering vibration. Therefore, when a task A to determine the transition from the SBW to the EPS state, and a task E to execute the EPS control are set within the control cycle (5 msec), the task E is set to be started in synchronization with the termination of the task A. When the power steering control for the EPS control is started, the time "lag" is eliminated to prevent the steering vibration.