Furthermore, in the present working example 4, the central part of the heat sink 104 in the transverse direction Y serves as the narrow-pitch section 11, and the wide-pitch sections 12 are configured (disposed) on both sides thereof in the Y-direction. However, the spacing between the fin plates 203 can be appropriately modified in accordance with the design of the heat exchanger. For example, the central part in the transverse direction Y may be designed to serve as the wide-pitch section 12, and the narrow-pitch sections 11 may be configured (disposed) on both sides thereof. In addition, a configuration can also be adopted such that, for example, the spacing between the fin plates 203 gradually narrows or gradually widens toward the center in the transverse direction Y. Furthermore, it is also possible to make it such that one half in the transverse direction Y serves as the narrow-pitch section 11 and the remaining (other) half constitutes the wide-pitch section 12.

A fin plate 205 according to working example 5 of the present teachings includes cut-and-raised parts 27. As shown in FIG. 13, the fin plate 205 of the present working example 5 has a substantially oblong (e.g., rectangular) shape in a side view. In addition, the fin plate 205 comprises a plurality of the cut-and-raised parts 27, which is disposed at (in) a central part in a side view, and a perimetric-edge part (periphery) 271, which surrounds the outer perimeter of the cut-and-raised parts 27. The latching grooves 21 of the fin plate 205 are formed on both sides in the plate-width direction at both end parts 23, 24 in the longitudinal direction.