The present invention is provided to suppress occurrence of free flow. An infusion pump includes: a sliding clamp closing and releasing an infusion tube; a pump body including a tube attachment portion to which the infusion tube is to be attached detachably and forcibly transferring liquid in the infusion tube; and a door pivotably supported by the pump body so that the tube attachment portion is openable and closable by the door. The pump body includes: a clamp attachment portion into which the sliding clamp having the infusion tube set therein is to be inserted and set; and a release operator being operated in the clamp attachment portion to transfer the sliding clamp from a close mode to a release mode, the release operator being configured to be locked, in response to opening movement of the door, so that the release operator is inoperable for releasing, and to be unlocked in response to closing movement of the door.