A hemodialysis apparatus includes a blood processing machine, a blood circuit through which blood led from a patient flows, a blood pump attached to the blood circuit to pump blood, a dialysate circuit, a clamp disposed downstream of the blood pump for the blood circuit to block the blood circuit, a blood pressure sensor for detecting the pressure of a part of the blood circuit between the blood pump and the blocker, and a control unit connected with the blood pump and the blood pressure sensor. The control unit is configured to determine, based on the pressure detected by the blood circuit pressure detector, whether or not the blood circuit has encountered abnormal conditions while the blood circuit blocked by the clamp is filled with liquid by the blood pump (steps SA2, SA3, and SA5).
