A bubble separator used in a fluid circuit for an automobile and that separates bubbles in a refrigerant may include a swirl flow formation part extending in a substantially horizontal direction, and including an internal space having a columnar shape. The bubble separator may also include a flow inlet disposed at one end of the swirl flow formation part, and being open so as to cause the refrigerant to flow in the flow inlet in a tangential direction of an inner peripheral surface of the swirl flow formation part and so as to form a swirl flow on the inner peripheral surface. The bubble separator may also include a flow outlet disposed at another end of the swirl flow formation part, and being open so as to cause the refrigerant to flow out of the flow outlet in a tangential direction from the inner peripheral surface. The bubble separator may further include a gas discharge port to discharge gas separated from the refrigerant in the swirl flow formation part outside of the swirl flow formation part, and at least one liquid drop nozzle provided on a wall surface of the swirl flow formation part.