To provide a two-layer vertical screw press in which the installation area is reduced, the throughput of an original liquid is increased without lowering dehydration capacity and continuous operation is made possible.

The installation area of a vertical screw press is reduced by providing an outer screw (4) and an inner screw (5) inside an outer screen (2) and an inner screen (3) which are concentric. An original liquid supply passage (27) is formed on the driving shaft (13) connected to the inner screw (5), this original liquid supply passage (27) communicates with an outer filtration chamber (8) and an inner filtration chamber (9) and, by the filtration chambers combined doubly and difference speed rotation, the large quantity of the original liquid can be processed. The outer filtration chamber (8), an outer filtration chamber passage (39) and an inner filtration chamber passage (40) are provided on the back pressure plate (22) of the two-layer vertical screw press (1) and a discharge chamber (36) in which a raking blade (38) is arranged is formed under the back pressure plate (22), then high squeeze is made possible with the back pressure plate (22) and the discharge chamber (36).