An evaporator includes a first heat exchanger and a second heat exchanger. The first heat exchanger includes a first path in which coolant flows downwardly, a second path in which the coolant from the first path flows upwardly, and a third path in which the coolant from the second path flows downwardly. The second heat exchanger includes at least two paths including a first path in which the coolant from the first heat exchanger flows upwardly. The number of tubes in the first path of the first heat exchanger is smaller than that in any one of the other paths of the exchangers. The number of tubes in the second path of the first heat exchanger is equal to or greater than that in the third path of the first heat exchanger. The number of tubes in the first path of the second heat exchanger is smaller than that in the third path of the first heat exchanger.