The present invention provides a blood purification apparatus in which inadvertent replacement of a container bag attached to a hanger portion can be avoided. Provided is a blood purification apparatus including a holding device (2) capable of holding a container bag that contains a liquid for blood purification treatment, such as dialysate, substitution fluid, or anticoagulant, the blood purification apparatus being capable of performing blood purification treatment using the liquid in the container bag. The holding device (2) includes a hanger portion (2b) including an attachment portion (2c) to which the container bag can be attached, and movable between a use position in which the container bag is used and a replacement position in which the container bag is replaced, a measuring device (g) capable of measuring the weight of the container bag held by the hanger portion (2b), and a restricting device (6) that restricts attachment and detachment of the container bag to and from the attachment portion (2c) when the hanger portion (2b) is in the use position.
