A heat exchange element comprising: unit constituent members in a stacked manner, each of which unit constituent member is constituted of partition members, each of which partition member has heat-transfer properties and moisture permeability and spacing members that hold the partition members with a predetermined spacing, in which a primary air flow passes along upper-surface sides of the partition members and a secondary air flow passes through on under-surface sides of the partition members, and in which the primary air flow and the secondary air flow cross and exchange heat and moisture via the partition members, wherein the spacing member comprises first spacing ribs that are provided on the upper surface of the partition member with a predetermined spacing parallel to a direction of the primary air flow, second spacing ribs that are provided on the undersurface of the partition member with a predetermined spacing parallel to a direction of the secondary air flow, characterized by further comprising first deflection-suppressing ribs that are connected to the second spacing ribs, that are separate from the first spacing ribs and provided between the first spacing ribs parallel to each other with a predetermined spacing, and that have a height smaller than the first spacing ribs, and second deflection-suppressing ribs that are connected to the first spacing ribs, that are separate from the second spacing ribs and provided between the second spacing ribs parallel to each other with a predetermined spacing, and that have a height smaller than the second spacing ribs; characterized in that there are first sealing ribs that are provided on both sides of upper surface of the partition member, being parallel to a direction of the primary air flow; and second sealing ribs that are provided on both sides of undersurface of the partition member, being parallel to a direction of the secondary air flow, wherein the first spacing ribs are connected to the second sealing ribs, provided between the first sealing ribs, and parallel to each other with a predetermined spacing, the second spacing ribs are connected to the first sealing ribs, provided between the second sealing ribs, and parallel to each other with a predetermined spacing, the first deflection-suppressing ribs are connected to the second sealing ribs and provided between the first spacing ribs parallel to each other with a predetermined spacing, and the second deflection-suppressing ribs are connected to the first sealing ribs, and provided between the second spacing ribs parallel to each other with a predetermined spacing. each of which unit constituent member is constituted of partition members, each of which partition member has heat-transfer properties and moisture permeability and spacing members that hold the partition members with a predetermined spacing, in which a primary air flow passes along upper-surface sides of the partition members and a secondary air flow passes through on under-surface sides of the partition members, and in which the primary air flow and the secondary air flow cross and exchange heat and moisture via the partition members, wherein in which a primary air flow passes along upper-surface sides of the partition members and a secondary air flow passes through on under-surface sides of the partition members, and in which the primary air flow and the secondary air flow cross and exchange heat and moisture via the partition members, wherein the spacing member comprises first spacing ribs that are provided on the upper surface of the partition member with a predetermined spacing parallel to a direction of the primary air flow, second spacing ribs that are provided on the undersurface of the partition member with a predetermined spacing parallel to a direction of the secondary air flow, characterized by further comprising first spacing ribs that are provided on the upper surface of the partition member with a predetermined spacing parallel to a direction of the primary air flow, second spacing ribs that are provided on the undersurface of the partition member with a predetermined spacing parallel to a direction of the secondary air flow, characterized by further comprising first deflection-suppressing ribs that are connected to the second spacing ribs, that are separate from the first spacing ribs and provided between the first spacing ribs parallel to each other with a predetermined spacing, and that have a height smaller than the first spacing ribs, and second deflection-suppressing ribs that are connected to the first spacing ribs, that are separate from the second spacing ribs and provided between the second spacing ribs parallel to each other with a predetermined spacing, and that have a height smaller than the second spacing ribs;