A hemodialysis apparatus that is provided with a dialyzer which performs hemodialysis, a dialysate circuit composed of a dialysate supply passage for supplying fresh dialysate to the dialyzer and a dialysate recovery passage for recovering used dialysate having passed through the dialyzer, a dialysate pump provided in the dialysate recovery passage and feeding the used dialysate, draining means for drainage from blood through the dialyzer, a dialysate filter (41, 63) having an inside divided by a filtration film (41a, 63a) into a space on the inflow side (41 b, 63b) and a space on the discharge side (41 c, 63c) and purifying and discharging the fresh dialysate flowing from the dialysate supply passage, and control means (1 a) for controlling operations of the dialysate pump and the draining means, comprising: an inspection passage (43, 61 B) for connecting one of the space on the inflow side or the space on the discharge side of the dialysate filter (41, 63) to the dialysate recovery passage; opening means for opening the other space on the side opposite to the one space of the dialysate filter (41, 63) into the air; pressure detecting means for detecting pressure fluctuation in the one space; and judgment means for good or bad judgment of the dialysate filter (41, 63) on the basis of a detection result of the pressure detecting means, characterised in that when good or bad judgment of the dialysate filter (41, 63) is to be done, the control means (1 a) opens the other space into the air by the opening means and suctions the fluid in the one space through the inspection passage (43, 61 B) by operating the dialysate pump, stops the dialysate pump when the pressure detecting means detects that a pressure is reduced to a predetermined first negative pressure, continues suctioning from the one space by the draining means and when the pressure detecting means detects that the pressure in the one space is reduced to a predetermined second negative pressure lower than the first negative pressure, stops an operation of the draining means; and the judgment means monitors pressure fluctuation in the one space where the pressure is reduced to the second negative pressure by the pressure detecting means and determines that the dialysate filter (41, 63) is not acceptable when a pressure rise is detected. an inspection passage (43, 61 B) for connecting one of the space on the inflow side or the space on the discharge side of the dialysate filter (41, 63) to the dialysate recovery passage; opening means for opening the other space on the side opposite to the one space of the dialysate filter (41, 63) into the air; pressure detecting means for detecting pressure fluctuation in the one space; and judgment means for good or bad judgment of the dialysate filter (41, 63) on the basis of a detection result of the pressure detecting means, characterised in that when good or bad judgment of the dialysate filter (41, 63) is to be done, the control means (1 a) opens the other space into the air by the opening means and suctions the fluid in the one space through the inspection passage (43, 61 B) by operating the dialysate pump, stops the dialysate pump when the pressure detecting means detects that a pressure is reduced to a predetermined first negative pressure, continues suctioning from the one space by the draining means and when the pressure detecting means detects that the pressure in the one space is reduced to a predetermined second negative pressure lower than the first negative pressure, stops an operation of the draining means; and the judgment means monitors pressure fluctuation in the one space where the pressure is reduced to the second negative pressure by the pressure detecting means and determines that the dialysate filter (41, 63) is not acceptable when a pressure rise is detected.