By positioning a substantially conical channel-forming member inside a body (30) in which a swirling space (30a) for swirling a coolant is formed, an ejector (13) forms a nozzle channel which functions as a nozzle for depressurizing a coolant discharged from the swirling space (30a) between the channel-forming member and the inner circumferential surface of the body (30), and forms a diffuser channel for pressurizing a mixed coolant obtained by mixing a sprayed coolant sprayed from the nozzle channel with an aspirated coolant aspirated from an aspirating channel. Furthermore, a plurality of drive channels (36a) for guiding the coolant from a distribution space (30g) into the swirling space (30a) are formed in the body (30), and formed in a manner such that the coolant introduced to the swirling space (30a) from each of the drive channels (36a) flows along the outer perimeter of the swirling space (30a), and flows in directions which differ from one another. As a result, it is possible to sufficiently improve nozzle efficiency.