There is provided a heat exchange member that uses a honeycomb structure and exhibits an improved heat exchange ratio, a manufacturing method for the heat exchange member, and a heat exchanger that includes the heat exchange member. A heat exchange member (10) is provided with at least two honeycomb structures (1) arranged serially, the honeycomb structures (1) including a cell structural part having cells defined by walls including SiC and provided with channels in which a first fluid circulates by flowing from one end to the other end, and a circumferential wall provided on the circumference of the cell structural part. The first fluid circulates inside the cells of the honeycomb structures (1) without leaking to the outside or mixing. At least a pair of cell structural parts in the honeycomb structures (1) are arranged adjacent to each other with a gap (17) interposed therebetween among the honeycomb structures (1) arranged serially, and the first fluid circulating inside the cells mixes together between the ends that form the gap (17).