An optical apparatus includes a first element, a second element, a support which supports the first element, a first measuring device which measures the position of the first element relative to the support, a second measuring device which measures the position of the second element relative to the support, a third measuring device which measures any deformation of the support, and a controller. The controller controls the relative position between the first element and the second element on the basis of the measurement results obtained by the first measuring device, the second measuring device, and the third measuring device.