When an operating point that is determined by the engine speed (Ne), the engine torque (Te), and the vehicle speed falls within the zones of both a first vibration risk region (α1) and a second vibration risk region (α2), the dwell time (ΔT1) thereof is measured, and once this dwell time (ΔT1) reaches a predetermined vibration assessment time (ΔT1_Lim), the gear ratio of the continuously variable transmission is corrected towards the large side (low side) so that the operating point is moved out of the vibration risk regions (α1, α2).