Tunnel dryer, suitable for drying mouldings, with - a plurality of carriers for carrying the mouldings, which are arranged lying one behind the other along a tunnel passage in a cavity of a tunnel, wherein the cavity of the tunnel is delimited by a bottom, two opposing side walls and a top wall; - a feeding device for feeding drying air into the tunnel, - a plurality of air inlets, arranged lying longitudinally one behind the other, in the form of diffuser boxes, which are arranged lying respectively transversely opposite one another on both sides of the passage and are directed towards the passage, wherein the air inlets are respectively formed by air diffusing plates with holes arranged mirror-invertedly and parallel above and below the carriers, wherein the air diffusing plates with holes are arranged in the bottom regions of the diffuser boxes that are facing the carriers, wherein during operation the air inlets respectively produce a flow circulation, with which air can be removed at at least one air outlet in the tunnel and can be introduced again through the air inlets; characterized in that - the dryer also comprises a conveying device, for conveying the carriers in a conveying direction through the tunnel passage, wherein the carriers are formed by flat and air-permeable carrying elements, which can be moved through the passage in the conveying direction extending in the longitudinal direction of the tunnel dryer, wherein the carrying elements are respectively formed by a perforated plate or a grating and the conveying device is designed to convey the carriers through the passage in the conveying direction in a single conveying plane; - the air inlets form multiple air-feeding part-devices (11.1 to 11.11 or 11.12), arranged lying one behind the other along the passage, wherein the air inlets are respectively formed by a hollow, flat and, in plan view, rectangular diffusing box, which has closed circumferential walls and a top wall, wherein the air diffusing plate is arranged in the lower region of the diffusing box as a bottom wall; - the air outlet is located in a side wall of the tunnel. - a plurality of carriers for carrying the mouldings, which are arranged lying one behind the other along a tunnel passage in a cavity of a tunnel, wherein the cavity of the tunnel is delimited by a bottom, two opposing side walls and a top wall; - a feeding device for feeding drying air into the tunnel, - a plurality of air inlets, arranged lying longitudinally one behind the other, in the form of diffuser boxes, which are arranged lying respectively transversely opposite one another on both sides of the passage and are directed towards the passage, wherein the air inlets are respectively formed by air diffusing plates with holes arranged mirror-invertedly and parallel above and below the carriers, wherein the air diffusing plates with holes are arranged in the bottom regions of the diffuser boxes that are facing the carriers, wherein during operation the air inlets respectively produce a flow circulation, with which air can be removed at at least one air outlet in the tunnel and can be introduced again through the air inlets; characterized in that - the dryer also comprises a conveying device, for conveying the carriers in a conveying direction through the tunnel passage, wherein the carriers are formed by flat and air-permeable carrying elements, which can be moved through the passage in the conveying direction extending in the longitudinal direction of the tunnel dryer, wherein the carrying elements are respectively formed by a perforated plate or a grating and the conveying device is designed to convey the carriers through the passage in the conveying direction in a single conveying plane; - the air inlets form multiple air-feeding part-devices (11.1 to 11.11 or 11.12), arranged lying one behind the other along the passage, wherein the air inlets are respectively formed by a hollow, flat and, in plan view, rectangular diffusing box, which has closed circumferential walls and a top wall, wherein the air diffusing plate is arranged in the lower region of the diffusing box as a bottom wall; - the air outlet is located in a side wall of the tunnel.