To automatically and continuously perform dehydration in a cake takeoff and refresh process by jetting compressed air from the back surfaces of a pair of filter cloths for filtering original liquid to remove the clogging of the filter cloths and the water stuck thereon.

This automatic, continuous dehydration press device consists of a filter chamber having an original liquid feeding means 7 and a pair of filter means 25a, 25b opposite to liquid filtrate discharge means 28, 29 and a hydraulic chamber 4 having a hydraulic means 46 for reciprocating one filter means 25a of the pair of filter means. In this case, the pair of filter means 25a, 25b consist of filter cloths 25a, 25b forming a filter space and filter cloth supporting means 24, 26 on which the filter cloths are fitted, and means 8, 8b for feeding compressed air from the back surface of the filter cloths 25a, 25b to between the fitting surfaces of the filter cloths 25a, 25b and the filter clothe supporting means 24, 26 are installed. In this way, shock waves generated by the compressed air fed in a refresh process of the filter cloths 25a, 25b, the clogging of the filter cloths 25a, 25b and the water stuck thereon can be removed.