To provide an extrusion manufacturing method which enables a significant decrease in the number of pallets by using the pallets in a circulating manner and saves on the manufacturing cost of a cement molded plate by enhancing the production efficiency.

A green molded product A obtained by molding a raw material by extrusion from an extrusion molder 1 and cutting it is disposed on a receiving pallet 2 which is moved circulating by a circulatory moving mechanism, and the pallet 2 is loaded onto an ascending/descending lifter for return circulation provided halfway through a route for the circulatory movement of the receiving pallet 2. Further, the green molded products A on the pallets 2 are transferred onto a curing pallet by a transfer loading means in such a way that a plurality of the green molded products A are aligned on the curing pallet. Finally, the curing pallet is sent into a steam curing chamber to cure and harden the green molded product A.