The present invention relates to a filling apparatus for filling containers with fluid products, and to the respective method, wherein the apparatus comprises a rest area arranged outside of a filling path and of a filling area, the rest area is accessible to the operator without interrupting the filling of the containers and actuating means to reciprocally move a first and a second filling unit from an operating condition to a rest condition; wherein in an operating condition one between a first and second filling unit is arranged in the filling area and able to be in fluid communication with the containers to be filled; and wherein in the rest condition the other between the first and second filling unit is arranged in the rest area accessible to the operator without interrupting the filling of the containers in the filling area.