PURPOSE: To provide a deck assembly for a rotation type drum filter capable of thermally expanding constituent elements without causing damage by installing division grids extending in the longitudinal direction of the outer circumference of the drum and arranging a corrugated sheet, etc., between the division grids.

CONSTITUTION: This filter deck assembly sliding seal is obtained by installing plural division grids 24 extending in the longitudinal direction at a prescribed interval parallel on the outer circumference of a drum 26, arranging an impermeable corrugated sheet 30 alternately having ridges 32 and channels 34 between adjacent pairs of the division grids 24 and defining the contour of filtrate compartments 28. Plural perforated filter plates 40 are attached to the top surface of each corrugated sheet 30 and a sealing member 50 is attached to the leading edge of each corrugated sheet 30. The sealing member 50 further has a leg 52 engaged between the filter plate 40 and the corrugated sheet 30 so as to sealingly abut the gap 64 between the filter plates 40 adjacent in the circumferential direction.