To easily and accurately conduct positioning for a pair of flanges with respect to plate-like tubes.

This oil cooler element 1 is provided with layered tubes 2, 6 layered plurally with the plural plate-like tubes 2 of which each is constituted of an oil-flowing fin plate 3, and an upper thin plate 4 and a lower thin plate 5 to sandwich the fin plate 3 while forming a space for forming a cooling water flowing passage, and the pair of flanges 9, 9. A flange positioning plate 13 having an engaging part 13a engaged with outer circumferences of the paired flanges 9, 9, and formed of a material having a brazing temperature and a thermal expansion coefficient equal to those of the plate-like tube 2 is joined by brazing, in the element.