Heat exchanger (1; 1'), in particular for a motor vehicle, - with a housing (3; 3') delimiting a housing interior space (2; 2'), wherein the housing interior space forms a first fluid channel (5a; 5a') for the passage of a first fluid (F 1; F 1 '), - with a plurality of channel elements (6; 6'), which are arranged adjacent to each other in the housing interior space (2; 2'), wherein each channel element (6; 6') comprises a channel housing (7; 7'), which delimit a channel interior space (8; 8') in each case, which forms a second fluid channel (5b; 5b') fluidically separated from the first fluid channel (F 1; F 1 ') for the passage of a second fluid (F 2; F 2 '), - wherein each channel element (6; 6') extends in an axial direction (A; A') so that the second fluid (F 2; F 2 ') can pass through the respective channel housing (7; 7') in the axial direction (A; A'), - wherein the channel elements (6; 6') are arranged adjacent to each other forming at least one channel line (9, 9') in a line direction (Z; Z') running at right angles to the axial direction (A; A'), characterised in that - the channel housing has a first housing wall in cross section perpendicular to the axial direction and a second housing wall lying substantially in parallel opposite the first housing wall, wherein the first housing wall has a first wall length (l 1) in cross section, which is greater than a wall length (l 2) of the second housing wall, - the first and second housing wall (12a, 12b) are completed by a third housing wall and a fourth housing wall lying opposite the third housing wall to form the channel housing, wherein the third and fourth housing wall (12c, 12d) are arranged at an acute angle (w) to each other in cross section vertical to the axial direction. - with a housing (3; 3') delimiting a housing interior space (2; 2'), wherein the housing interior space forms a first fluid channel (5a; 5a') for the passage of a first fluid (F 1; F 1 '), - with a plurality of channel elements (6; 6'), which are arranged adjacent to each other in the housing interior space (2; 2'), wherein each channel element (6; 6') comprises a channel housing (7; 7'), which delimit a channel interior space (8; 8') in each case, which forms a second fluid channel (5b; 5b') fluidically separated from the first fluid channel (F 1; F 1 ') for the passage of a second fluid (F 2; F 2 '), - wherein each channel element (6; 6') extends in an axial direction (A; A') so that the second fluid (F 2; F 2 ') can pass through the respective channel housing (7; 7') in the axial direction (A; A'), - wherein the channel elements (6; 6') are arranged adjacent to each other forming at least one channel line (9, 9') in a line direction (Z; Z') running at right angles to the axial direction (A; A'), characterised in that - the channel housing has a first housing wall in cross section perpendicular to the axial direction and a second housing wall lying substantially in parallel opposite the first housing wall, wherein the first housing wall has a first wall length (l 1) in cross section, which is greater than a wall length (l 2) of the second housing wall, - the first and second housing wall (12a, 12b) are completed by a third housing wall and a fourth housing wall lying opposite the third housing wall to form the channel housing, wherein the third and fourth housing wall (12c, 12d) are arranged at an acute angle (w) to each other in cross section vertical to the axial direction.