A vibration isolator determines a speed of a vibration applied to a camera with a vibration speed sensor, and differentiates and integrates the speed, and corrects the integrated value to zero when the differentiated value is zero, and determines the position of the correcting optical system according to the integrated value. Thus, an oscillation center of the correcting optical system is appropriately set at the origin, and an unwanted influence due to noise components in an output signal from the vibration speed sensor can be eliminated. Therefore, the vibration isolator can appropriately prevent an image blur.