A molding machine for producing a mold by applying external force of either pressurized air or mechanical compaction or both to molding sand (12) that is held in a mold space is disclosed. The mold space is defined by a master plate (9), which has a pattern (8), and a flask (7). The molding machine includes a lifter table (11) for vertically carrying the master plate (9) and the flask (7), a filling frame (4) disposed for vertical movement above the lifter table (10), and a reinforcing frame (5) disposed for vertical movement between the filling frame (4) and the lifter table (10). The reinforcing frame (5) and the flask (7) are adapted to approach each other such that the reinforcing frame (5) contacts the outer surface of the flask (7) to reinforce it.