Evaporator and refrigerator

An evaporator includes: a vessel having a refrigerant inlet for receiving a refrigerant at a lower part of the vessel, and a refrigerant outlet for discharging the refrigerant in an evaporated state at an upper part of the vessel; and a plurality of heat-transfer tubes disposed so as to extend inside the vessel along a longitudinal direction of the vessel, and configured to transfer heat received from a fluid flowing inside the heat-transfer tubes to the refrigerant flowing outside the heat-transfer tubes. The plurality of heat-transfer tubes are disposed so that at least one downward flow passage is defined through the plurality of heat-transfer tubes or around the plurality of heat-transfer tubes, the at least one downward flow passage having a width larger than a representative interval between the plurality of heat-transfer tubes. A representative interval between the plurality of heat-transfer tubes disposed on an upper side among the plurality of heat-transfer tubes is larger than a representative interval between the plurality of heat-transfer tubes disposed on a lower side among the plurality of heat-transfer tubes.