An apparatus comprising a peristaltic pump and an installation member including a flexible tube that is to be detachably attached to the peristaltic pump, wherein the peristaltic pump including: a rotor that is rotatably driven in an attachment recessed portion; and a roller that is formed in the rotor and that causes the fluid to flow in the flexible tube to be peristaltic by imparting peristaltic motion to the flexible tube to be peristaltic attached to the attachment recessed portion in a longitudinal direction in association with rotation of the rotor while compressing the flexible tube to be peristaltic in a radial direction, wherein the installation member comprises: - a main body that is attachable to a predetermined portion of the stator of peristaltic pump, and that is formed integrally with one of an upstream-side fixing portion (Da) and a downstream-side fixing portion (Db) of the flexible tube to be peristaltic; and - a notch portion that is formed in the main body, and that allows the other one of the upstream-side fixing portion (Da) and the downstream-side fixing portion (Db) of the flexible tube to be peristaltic to be positioned, characterized in that the peristaltic pump comprises a stator including the attachment recessed portion in which the flexible tube to be peristaltic, which allows a fluid such as blood to flow, is attached; - wherein the flexible tube i of the installation member is disposed in the attachment recessed portion of the stator of the peristaltic pump in a state where the main body of the installation member is attached to the stator. a rotor that is rotatably driven in an attachment recessed portion; and a roller that is formed in the rotor and that causes the fluid to flow in the flexible tube to be peristaltic by imparting peristaltic motion to the flexible tube to be peristaltic attached to the attachment recessed portion in a longitudinal direction in association with rotation of the rotor while compressing the flexible tube to be peristaltic in a radial direction, wherein the installation member comprises: - a main body that is attachable to a predetermined portion of the stator of peristaltic pump, and that is formed integrally with one of an upstream-side fixing portion (Da) and a downstream-side fixing portion (Db) of the flexible tube to be peristaltic; and - a notch portion that is formed in the main body, and that allows the other one of the upstream-side fixing portion (Da) and the downstream-side fixing portion (Db) of the flexible tube to be peristaltic to be positioned, characterized in that the peristaltic pump comprises a stator including the attachment recessed portion in which the flexible tube to be peristaltic, which allows a fluid such as blood to flow, is attached; - wherein the flexible tube i of the installation member is disposed in the attachment recessed portion of the stator of the peristaltic pump in a state where the main body of the installation member is attached to the stator. - a main body that is attachable to a predetermined portion of the stator of peristaltic pump, and that is formed integrally with one of an upstream-side fixing portion (Da) and a downstream-side fixing portion (Db) of the flexible tube to be peristaltic; and - a notch portion that is formed in the main body, and that allows the other one of the upstream-side fixing portion (Da) and the downstream-side fixing portion (Db) of the flexible tube to be peristaltic to be positioned, characterized in that the peristaltic pump comprises a stator including the attachment recessed portion in which the flexible tube to be peristaltic, which allows a fluid such as blood to flow, is attached; - wherein the flexible tube i of the installation member is disposed in the attachment recessed portion of the stator of the peristaltic pump in a state where the main body of the installation member is attached to the stator.