Apparatus for the two-sided coating of at least one running flat material web, - with a first and a second coating nozzle (2, 3), wherein the first coating nozzle is providable to the first side of the flat material web and the second coating nozzle is providable to the second side of the flat material web, in order to coat the respective side of the flat material web, and wherein at least one, preferably both, coating nozzles (2, 3) are transferable from a working position into a maintenance position (A, W) and back, as well as - with supply line sections (4, 8) with throughflow channels (4a, 8a) that are embodied therein and that are connected with one another in the working position and that ensure a throughflow for supplying a hot, liquid coating material to the respective coating nozzle (2, 3), characterized in that, during the transferring of at least one of the said coating nozzles (2, 3) from the working position into the maintenance position (A, W), a first rigid supply line section and a second rigid supply line section (4, 8), which in the working position enable a throughflow of the coating material to the coating nozzle (2, 3), are automatically moved relative to one another in such a manner so that the throughflow channels (4a, 8a) embodied in them are moved relative to one another in order to interrupt the throughflow of the coating material to this coating nozzle (2, 3). - with a first and a second coating nozzle (2, 3), wherein the first coating nozzle is providable to the first side of the flat material web and the second coating nozzle is providable to the second side of the flat material web, in order to coat the respective side of the flat material web, and wherein at least one, preferably both, coating nozzles (2, 3) are transferable from a working position into a maintenance position (A, W) and back, as well as wherein the first coating nozzle is providable to the first side of the flat material web and the second coating nozzle is providable to the second side of the flat material web, in order to coat the respective side of the flat material web, and wherein at least one, preferably both, coating nozzles (2, 3) are transferable from a working position into a maintenance position (A, W) and back, as well as - with supply line sections (4, 8) with throughflow channels (4a, 8a) that are embodied therein and that are connected with one another in the working position and that ensure a throughflow for supplying a hot, liquid coating material to the respective coating nozzle (2, 3), characterized in that, during the transferring of at least one of the said coating nozzles (2, 3) from the working position into the maintenance position (A, W), a first rigid supply line section and a second rigid supply line section (4, 8), which in the working position enable a throughflow of the coating material to the coating nozzle (2, 3), are automatically moved relative to one another in such a manner so that the throughflow channels (4a, 8a) embodied in them are moved relative to one another in order to interrupt the throughflow of the coating material to this coating nozzle (2, 3). characterized in that, during the transferring of at least one of the said coating nozzles (2, 3) from the working position into the maintenance position (A, W), a first rigid supply line section and a second rigid supply line section (4, 8), which in the working position enable a throughflow of the coating material to the coating nozzle (2, 3), are automatically moved relative to one another in such a manner so that the throughflow channels (4a, 8a) embodied in them are moved relative to one another in order to interrupt the throughflow of the coating material to this coating nozzle (2, 3).