A control apparatus includes: a motor; a driving body rotated by the motor; a rotary encoder including a disk and a sensor; a detector detecting a rotation position and a rotation velocity of the disk based on a signal outputted from the sensor; and a controller. The disk is fixed to the driving body in a state of being eccentric to a rotational axis of the driving body, and the sensor reads a scale of the disk and outputs a pulse signal depending on rotation of the disk. The controller generates velocity data indicating a locus of the rotation velocity with respect to the rotation position; specifies a position-phase relation between the rotation position of the disk and a rotation phase of the driving body; and controls at least one of the rotation of the driving body and displacement of an object being displaced by action from the driving body.