An optical system driving device includes a movable body that is movable in at least three degrees of freedom, and a light transmissive unit integrally mounted to the movable body. The optical system driving device also includes a driving unit that moves the movable body in at least three degrees of freedom, and a detection unit that detects a position of the movable body in each of at least three degrees of freedom. The detection unit includes a light-emitting unit that emits light toward the light transmissive unit, and an optical detector that receives light emitted from the light-emitting unit and passing through the light transmissive unit and outputs a light-receiving signal based on the received light. The detection unit also detects a position of the movable body in each of at least three degrees of freedom based on the light-receiving signal from the optical detector.