Heat exchanger and inner fin thereof

A heat exchanger comprising:

• an outer packaging body provided with an inlet, an outlet, and a pair of opposing walls;
• and
• a corrugated inner fin disposed between the pair of opposing walls and provided with a concave portion and a convex portion alternately and continuously,
• wherein a heat exchange medium flows into an inner fin installation portion in the outer packaging body from the inlet, passes through the inner fin installation portion, and flows out of the outlet,
• wherein the outer packaging body is formed of an outer packaging laminate material in which a resin heat-fusible layer is provided on an inner surface side of a metal heat transfer layer,
• wherein the inner fin is formed of an inner core laminate material in which a heat-fusible layer is provided on both surface sides of a metal heat transfer layer,
• wherein the inner fin is formed in a rectangular wave shape in which a concave bottom wall and a convex top wall are arranged parallel to the pair of opposing walls, and a rising wall connecting the concave bottom wall and the convex top wall is arranged perpendicular to the pair of opposing walls, and
• wherein the concave bottom wall and the convex top wall of the inner fin and the pair of opposing walls of the outer packaging body are joined.