Heat exchanging element and heat exchange ventilator

A heat exchanging element comprising a first passage forming member and a second passage forming member stacked alternately, the heat exchanging element including a counterflow part that includes a first passage through which air passes and a second passage through which air flows in a direction opposite a direction in which the air passes through the first passage, wherein

• the first passage forming member and the second passage forming member each include:
• a rib portion, which constitutes the counterflow part, including a first wall portion constituting an end in a first direction of the first passage, a second wall portion constituting an end in the first direction of the second passage, and a third wall portion separating the first passage and the second passage adjacent to each other in a second direction from each other, the first direction being a direction in which the first passage forming member and the second passage forming member are stacked, the second direction being perpendicular to the first direction;
• and
• a board being in contact with an end in a third direction of the rib portion, and separating a first connection passage communicating with the first passage and a second connection passage communicating with the second passage from each other, the third direction being perpendicular to the first direction and to the second direction, wherein
• the third wall portion has a thickness smaller than a thickness of the first wall portion and smaller than a thickness of the second wall portion.