To reduce contrast unevenness of a liquid crystal display by reducing variations of electric characteristic of active elements while reducing variations of a cooling speed in an annealing processing in the manufacturing method of a liquid crystal display device.

Air flow control plates 61, 62, 63 are installed at the downstream side of an air blowing port 42. The air flow control plates 61, 62, 63 are stainless steel plates and each is provided with a air flow control surface such as to gradually approach toward the downstream from the position most separated from a carrier 30 in the front face of the air blowing port 42 to the carrier 30. Consequently, the air control surfaces even in each air flow control plate act so as to squeeze air flows to be blown out form widely air blowing ports 41, 42 toward carrier 30 as the air flows progress to the downstream. These air flow control surfacers are formed into smoothly bent curved surfaces so as not to disturbe air flows as much as possible.