While a vehicle incorporating an active vibration noise control apparatus is decelerating, hysteresis is given if an operating point moves from an operating point on a sampling period characteristic curve to an operating point on another sampling period characteristic curve. Even if a base period detected depending on noise contains fluctuations, a smooth noise control process is performed. Since a division number produced when the base period is divided by a sampling period is a real number, the freedom of design is widened. Less strict limits are posed on the processing capability of a CPU of the active vibration noise control apparatus to provide a wider control range.