A blood purification apparatus comprising: a blood purifier which includes a blood purification membrane and performs the blood purification in the blood purification membrane; an arterial blood circuit, a proximal end of which is connected to the blood purifier and in which a blood pump is disposed in the middle thereof; a venous blood circuit, a proximal end of which is connected to the blood purifier; a dialysate introduction line which introduces a dialysate into the blood purifier; a dialysate discharge line which discharges the dialysate from the blood purifier; a dialysate infusing line, one end of which is connected to a collection port formed in a predetermined part of the dialysate introduction line, and the other end of which is connected to the arterial blood circuit or the venous blood circuit; and a dialysate infusing pump which is disposed in the dialysate infusing line and is able to supply the dialysate of the dialysate introduction line to the arterial blood circuit or the venous blood circuit, wherein a closed circuit is formed in a flow route of the dialysate of the dialysate introduction line side including the predetermined part formed with the collection port, and a test process for confirming the connection of the dialysate infusing line to the collection port by measuring a fluid pressure in the closed circuit while driving the dialysate infusing pump is performed, the blood purification apparatus further comprising: a measurement device capable of measuring a fluid pressure in the closed circuit of the state where the dialysate infusing pump is driven in the test process; a determination device for determining whether or not the dialysate infusing line is connected normally to the collection port based on a measured value of the measurement device; and a control device formed with a storage device and the determination device, characterised in that the control device is configured to perform the test process. a blood purifier which includes a blood purification membrane and performs the blood purification in the blood purification membrane; an arterial blood circuit, a proximal end of which is connected to the blood purifier and in which a blood pump is disposed in the middle thereof; a venous blood circuit, a proximal end of which is connected to the blood purifier; a dialysate introduction line which introduces a dialysate into the blood purifier; a dialysate discharge line which discharges the dialysate from the blood purifier; a dialysate infusing line, one end of which is connected to a collection port formed in a predetermined part of the dialysate introduction line, and the other end of which is connected to the arterial blood circuit or the venous blood circuit; and a dialysate infusing pump which is disposed in the dialysate infusing line and is able to supply the dialysate of the dialysate introduction line to the arterial blood circuit or the venous blood circuit, wherein a closed circuit is formed in a flow route of the dialysate of the dialysate introduction line side including the predetermined part formed with the collection port, and a test process for confirming the connection of the dialysate infusing line to the collection port by measuring a fluid pressure in the closed circuit while driving the dialysate infusing pump is performed, the blood purification apparatus further comprising: a measurement device capable of measuring a fluid pressure in the closed circuit of the state where the dialysate infusing pump is driven in the test process; a determination device for determining whether or not the dialysate infusing line is connected normally to the collection port based on a measured value of the measurement device; and a control device formed with a storage device and the determination device, characterised in that the control device is configured to perform the test process. a measurement device capable of measuring a fluid pressure in the closed circuit of the state where the dialysate infusing pump is driven in the test process; a determination device for determining whether or not the dialysate infusing line is connected normally to the collection port based on a measured value of the measurement device; and a control device formed with a storage device and the determination device, characterised in that the control device is configured to perform the test process.