A reserve tank includes a plurality of chambers, including a first chamber, a second chamber, and at least one intermediate chamber, a first inflow port connected to the first chamber, a first outflow port connected to the first chamber, a second inflow port connected to the second chamber, a second outflow port connected to the second chamber, and a plurality of partition walls separating the chambers. Each of the partition walls is provided with a corresponding one of a plurality of refrigerant flow ports. A specific refrigerant flow port includes a first through hole and a second through hole that pass through a specific partition wall and are separated from each other. The specific refrigerant flow port being a refrigerant flow port provided in the specific partition wall among the partition walls.