Method for loading pieces (P) on a carriage comprising: - a frame which is provided with a plurality of wheels to move, when in use, on a floor (F, F'); - at least one first support surface which is connected with said frame ; - at least one second support surface which is placed above said at least one first support surface and connected with said frame in a movable way between an operative position, where said at least one second support surface is placed substantially horizontal such as to allow laying at least one piece (P) on said at least one second support surface , and an inactive position, where said at least one second support surface is placed such as to keep free the upper part of said at least one first support surface to allow laying at least one piece (P) on said at least one first support surface ; and - an automatic loading device; said method comprising the following steps: - positioning said at least one second support surface in said inactive position; - loading at least one piece (P) on said at least one first support surface ; - moving said at least one second support surface from said inactive position to said operative position; and - loading at least one piece (P) on said at least one second support surface positioned in said operative position; wherein at least one of said steps of: - positioning said at least one second support surface in said inactive position; - loading at least one piece (P) on said at least one first support surface ; - moving said at least one second support surface from said inactive position to said operative position; - loading at least one piece (P) on said at least one second support surface positioned in said operative position; is performed by means of said automatic loading device. - a frame which is provided with a plurality of wheels to move, when in use, on a floor (F, F'); - at least one first support surface which is connected with said frame ; - at least one second support surface which is placed above said at least one first support surface and connected with said frame in a movable way between an operative position, where said at least one second support surface is placed substantially horizontal such as to allow laying at least one piece (P) on said at least one second support surface , and an inactive position, where said at least one second support surface is placed such as to keep free the upper part of said at least one first support surface to allow laying at least one piece (P) on said at least one first support surface ; and - an automatic loading device; - positioning said at least one second support surface in said inactive position; - loading at least one piece (P) on said at least one first support surface ; - moving said at least one second support surface from said inactive position to said operative position; and - loading at least one piece (P) on said at least one second support surface positioned in said operative position; - positioning said at least one second support surface in said inactive position; - loading at least one piece (P) on said at least one first support surface ; - moving said at least one second support surface from said inactive position to said operative position; - loading at least one piece (P) on said at least one second support surface positioned in said operative position; <EOS>