A blood purification apparatus comprising: a blood circuit including an arterial blood circuit and a venous blood circuit and that is capable of extracorporeally circulating blood of a patient from a distal end of the arterial blood circuit to a distal end of the venous blood circuit; a blood purification device provided between the arterial blood circuit and the venous blood circuit of the blood circuit and that is capable of purifying the blood flowing in the blood circuit; a dialysate introduction line for introducing dialysate into the blood purification device and a dialysate drain line for discharging drain liquid from the blood purification device; a liquid delivery pump provided to the dialysate introduction line and that is capable of causing the dialysate in the dialysate introduction line to flow; a heating device (h) that is capable of heating the dialysate to be introduced from the dialysate introduction line into the blood purification device; a temperature-detecting device that is capable of detecting a temperature of the dialysate heated by the heating device (h); and a control device that is capable of controlling at least the liquid delivery pump and the heating device (h), wherein the control device is configured such that, if a dialysate temperature detected by the temperature-detecting device is higher than or equal to a predetermined value, the liquid delivery pump is controlled to cause the dialysate in the heating device (h) to flow to an upstream side or a downstream side with respect to the heating device (h) without allowing the dialysate to be introduced into the blood purification device characterized in that the liquid delivery pump is a peristaltic pump that is capable of undergoing normal rotation and reverse rotation, and wherein the control device is configured such that, if the dialysate temperature detected by the temperature-detecting device is higher than or equal to the predetermined value, the liquid delivery pump is controlled to cause the dialysate in the heating device (h) to flow to an upstream portion of the dialysate introduction line by undergoing reverse rotation.. a blood circuit including an arterial blood circuit and a venous blood circuit and that is capable of extracorporeally circulating blood of a patient from a distal end of the arterial blood circuit to a distal end of the venous blood circuit; a blood purification device provided between the arterial blood circuit and the venous blood circuit of the blood circuit and that is capable of purifying the blood flowing in the blood circuit; a dialysate introduction line for introducing dialysate into the blood purification device and a dialysate drain line for discharging drain liquid from the blood purification device; a liquid delivery pump provided to the dialysate introduction line and that is capable of causing the dialysate in the dialysate introduction line to flow; a heating device (h) that is capable of heating the dialysate to be introduced from the dialysate introduction line into the blood purification device; a temperature-detecting device that is capable of detecting a temperature of the dialysate heated by the heating device (h); and a control device that is capable of controlling at least the liquid delivery pump and the heating device (h), wherein the control device is configured such that, if a dialysate temperature detected by the temperature-detecting device is higher than or equal to a predetermined value, the liquid delivery pump is controlled to cause the dialysate in the heating device (h) to flow to an upstream side or a downstream side with respect to the heating device (h) without allowing the dialysate to be introduced into the blood purification device characterized in that the liquid delivery pump is a peristaltic pump that is capable of undergoing normal rotation and reverse rotation, and wherein the control device is configured such that, if the dialysate temperature detected by the temperature-detecting device is higher than or equal to the predetermined value, the liquid delivery pump is controlled to cause the dialysate in the heating device (h) to flow to an upstream portion of the dialysate introduction line by undergoing reverse rotation..