A molding machine which allows a simplification of a sand filling operation, and the prevention of the formation of a bridge and an air channel in the sand tank, so that the sand filling operation of the molding machine is able to be performed steadily. The molding machine of the present invention includes: a sand tank for storing molding sand to be introduced to a molding flask; a pair of upper and lower sand filling nozzles to guide the molding sand in a horizontal direction, where the molding sand is supplied from a pair of upper and lower sand introducing parts which are located at the lower part of the sand tank; and at least one filter part with a plurality of air-injecting apertures on its entire body, which is attached to at least the entire inner surfaces of the pair of sand introducing parts; wherein the molding sand is fluidized by air injected through the air-injecting apertures of the filter part, and introduced to the molding flask through the sand filling nozzles.