Heat exchange core and heat exchanger

A heat exchange core comprising:

• a header flow path extending in a first direction;
• and
• a plurality of branching flow paths connected to the header flow path and extending in a second direction intersecting with the first direction, wherein
• a first angle formed by the header flow path with respect to a virtual connection plane between the header flow path and the plurality of branching flow paths is less than a second angle formed by the plurality of branching flow paths with respect to the connection plane,
• an end portion of a partition wall separating the plurality of branching flow paths is positioned to be separated from the connection plane in the second direction, and
• a distance between the end portion and the connection plane is 0.3 times or more and 2 times or less of a flow path width of the header flow path as viewed in a direction orthogonal to a reference plane including the header flow path and the plurality of branching flow paths.