A heat exchanger includes: stacked tubes through which a refrigerant flows; and a fin joined to the tube to increase a heat exchange area with air flowing around the tube. A cross-section of the fin perpendicular to a flow direction of the air is shaped in a wave shape that has: planar sections substantially parallel to the flow direction of the air; and a top for connecting between the adjacent planar sections. A clearance is defined in the planar section of the fin. When a portion of the fin where the shortest distance from a center line between the adjacent planar sections becomes the maximum is set as a furthest section in a cross-section perpendicular to a stacking direction of the tubes, the clearance is defined in one furthest section or at least one of a plurality of furthest sections.