Refrigerant evaporator

A refrigerant evaporator that exchanges heat between fluid flowing outside to be cooled and refrigerant, comprising:

• a first evaporation unit and a second evaporation unit disposed in series in a flow direction of the fluid, wherein
• each of the first evaporation unit and the second evaporation unit has a heat-exchanging core portion in which a plurality of tubes are stacked, the refrigerant flowing through the plurality of tubes,
• the heat-exchanging core portion of the first evaporation unit has a first core portion defined by a part of the plurality of tubes and a second core portion defined by a rest of the plurality of tubes, and
• the heat-exchanging core portion of the second evaporation unit has a third core portion defined by a part of the plurality of tubes opposing at least a part of the first core portion in the flow direction of the fluid and a fourth core portion defined by a part of the plurality of tubes opposing at least a part of the second core portion in the flow direction of the fluid;
• and
• a connection channel to connect a first refrigerant channel that introduces the refrigerant from the first core portion to the fourth core portion and a second refrigerant channel that introduces the refrigerant from the second core portion to the third core portion.