The invention relates to a heat exchanger, particularly for a motor vehicle, comprising a plurality of flat tubes (3), which are stacked parallel to each other in a stacking direction, and at least one collector (1, 2) for distributing a fluid to the flat tubes (3). At least one end of the flat tubes (3) opens out into the collector (1, 2). The collector (1, 2) comprises at least a first segment (1a-1d, 2a-2d) and a second segment (1a-1d, 2a-2d) adjacent thereto in the stacking direction, the segments (1a-1d, 2a-2d) being firmly bonded to each other. Each of the segments (1a-2d) has several passages (4) in a base region (5), said flat tubes (3) being inserted into the passages (4).