PURPOSE: To increase the area of filter cloth and to miniaturize a filter press, in the filter plate of the filter press used in the solid-liquid separation of various sludges or slurries, by forming the filter plate having filter cloths arranged to the surface and rear thereof into a curved shape.

CONSTITUTION: Filter cloths 8 are arranged to each of filter plates 1 so as to cover the recessed parts 2 provided to the surface and rear thereof and the respective filter plates 1 are mutually brought to a pressure contact state at the peripheral edge parts 3 thereof by a clamping apparatus at the time of use. The suspension 4 supplied to liquid supply ports 5 under pressure by a pump flows in the gaps between the respective filter plates 1 from groove parts 6 and the liquid transmitted through the filter cloths 8 passes through discharge ports 7 to be discharged to the outside and the residue, that is, the cake filtered by the filter cloths 8 is bonded to the surfaces of the filter cloths 8. By providing curved surfaces to each of the filter plates 1, each of the areas of the filter cloths 8 arranged to the surface and rear of each filter plate 1 becomes larger than the projection area of the filter plate 1 to a flat plate. Therefore, the area of the filter cloth is increased as compared with a flat filter plate having an equal projection area.