A heat exchanging member including a hollow pillar shaped honeycomb structure having partition walls defining cells, the cells penetrating from a first end face to a second end face to form flow paths for a first fluid, an inner peripheral wall, and an outer peripheral wall; and a covering member being configured to cover the outer peripheral wall of the pillar shaped honeycomb structure. The heat exchanging member is configured to perform heat exchange between the first fluid and a second fluid flowing through an outer side of the covering member. In the heat exchanging member, in a cross section of the pillar shaped honeycomb structure perpendicular to a flow path direction of the first fluid, the cells are radially provided, and each of the inner peripheral wall and the outer peripheral wall has a thickness larger than that of each of the partition walls.