A heat exchanger for medical use, comprising a tube bundle formed by a plurality of tubes having a straight axis for the conveyance of a primary fluid, which are embedded at their ends in disks located at the end faces of an outer jacket which is adapted to delimit, together with the disks, a portion of space for the containment of the tube bundle which is designed to be crossed by a secondary fluid, each tube having, at least at a portion of its length, a plurality of consecutive crimps adapted to determine a progressive variation of the shape of the passage section.