An ejector includes an atomization mechanism that is disposed at an end of a first nozzle and that atomizes a working fluid in a liquid phase while maintaining the liquid phase. The atomization mechanism includes an orifice and a collision plate. When the collision plate is orthographically projected onto a projection plane, in a projection of the collision plate, at least one point on a contour of the collision surface is disposed closer to a reference point than a second reference line, which is a line including the collision end point and perpendicular to the first reference line.