[Object] To provide a blood purification apparatus and a priming method for the same, which can reduce or dispense with dedicated components used for automated priming and which can reduce manufacturing costs of a blood circuit while achieving the automated priming. [Solution] There is provided a blood purification apparatus including a liquid level adjustment device A that can optionally introduce or discharge air into or from an upper portion of a venous air trap chamber 6, a control device C that can adjust a liquid level formed inside the venous air trap chamber 6 to have the height at any desired position by operating the liquid level adjustment device A, and a priming solution supplying line L3 that can supply a priming solution to an arterial blood circuit 1 and a venous blood circuit 2. During priming, the control device C can fill the arterial blood circuit 1 and the venous blood circuit 2 with priming solution supplied from the priming solution supplying line L3 by operating the liquid level adjustment device A at any desired timing.
