PURPOSE: To obtain a titled device which is capable of holding exactly and fixedly a gap between filtration faces by a supporting member when clamping a filter plate, by fitting a supporting member for holding a filtration face gap between filter plates, to a hanging member provided between the filter plate and filter cloth being adjacent to the filter plate.

CONSTITUTION: Projecting pieces 10,W are fitted to a filtration face 2 of a filter plate 5 in auxiliary filter cloth hung to the filter plate 5, and the end face of a fitting face 10a of each projecting piece 10 is opposed to each receiving seat 2a provided on the face 2. In this state, when the filter plates 5, 5 are clamped as shown by two pieces of left filter plates 5, 5, each projecting piece 10 fitted to the filter cloth 8 is made to press-contact with each receiving seat 2a of the face 2 through the filter cloth, as this filter plate 5 is clamped. Also, the end face of a projecting part 10b of each projecting piece 10 is butted through filter cloth 6, 6 to the end face of a projecting part 10b of each projecting piece 10 fitted to the filter cloth 8 of the adjacent filter plate 5, and a fixed gap W is held between both filtration faces 2, 2.