Heat exchanger and method for producing same

A method for producing a heat exchanger, the method comprising the steps of:

• preparing a heat exchange member comprising:
• a pillar shaped honeycomb structure comprising partition walls defining a plurality of cells, each of the cells extending from a first end face to a second end face to form a flow path for a first fluid, and an outer peripheral wall;
• and an inner cylindrical member fitted to the outer peripheral wall of the honeycomb structure;
• arranging an outer cylindrical member on a radially outer side of the inner cylindrical member with a distance such that at least a part of the outer cylindrical member forms a flow path for a second fluid;
• arranging an upstream cylindrical member having a cylindrical portion and a flange portion on a side of the first end face of the honeycomb structure and connecting an end portion of the flange portion to the inner cylindrical member and/or the outer cylindrical member;
• and
• arranging a downstream cylindrical member having a cylindrical portion and a flange portion on a side of the second end face of the honeycomb structure and connecting an end portion of the flange portion to the inner cylindrical member and/or the outer cylindrical member,
• wherein both axial end portions of the flow path for the second fluid are located on axially outer sides than the first end face and the second end face of the honeycomb structure, respectively, and
• wherein at least one of the upstream cylindrical member and the downstream cylindrical member has a rising position of the flange portion, the rising position being located on an axially inner side than the both axial end portions of the flow path for the second fluid.