A discharge device and method are disclosed that can discharge a discharge substance with a desired discharge amount at a desired flow rate. A storage unit provided in a discharge device includes a storage space which can store a discharge substance, and a discharge section which can discharge the discharge substance stored in the storage space toward the proximal side of a main body in an axial direction, and is configured to be capable of expanding deformation and contracting deformation in response to introduction and discharge of the discharge substance.
