Abstract: Provided is a heat exchanger in which first flow paths for flowing a first fluid and second flow paths for flowing a second fluid are arranged adjacent via a partition wall through which heat exchange is performed. The partition wall includes parallel tubular partition walls inside of which is the first flow paths. At least a part of the tubular partition walls in a flow path direction are integrally coupled to form a partition wall coupling portion having a geometric pattern in transverse cross section. An element figure of the geometric pattern corresponding to a transverse cross-sectional shape of the tubular partition wall is connected to each other at a vertex, and the number of sides of the element figure gathering at the vertex is an even number. In the partition wall coupling portion, the second flow paths are defined between outer peripheral surfaces of the surrounding tubular partition walls.

Abstract: Provided is a heat exchanger in which first flow paths for flowing a first fluid and second flow paths for flowing a second fluid are arranged adjacent via a partition wall through which heat exchange is performed. The partition wall includes parallel tubular partition walls inside of which is the first flow paths. At least a part of the tubular partition walls in a flow path direction are integrally coupled to form a partition wall coupling portion having a geometric pattern in transverse cross section. An element figure of the geometric pattern corresponding to a transverse cross-sectional shape of the tubular partition wall is connected to each other at a vertex, and the number of sides of the element figure gathering at the vertex is an even number. In the partition wall coupling portion, the second flow paths are defined between outer peripheral surfaces of the surrounding tubular partition walls.