PROBLEM TO BE SOLVED: To provide a means for a priming-system drainage line using a dialysate, which certainly prevents adhesion/accumulation of calcium carbonate at low cost without practically expending labor and a time, and can remove even calcium carbonate having already adhered and been accumulated.SOLUTION: In priming by a dialysate of arteriovenous blood circuits L1, L2 including a dialyzer D of an artificial dialysis apparatus, drainage treatment tablets T each formed by compressing and molding acidic agent powder are charged in a drainage funnel 1 provided in an inlet part of a priming drainage line L5.
