An indoor unit comprising: a casing including an air outlet; and a louver including a first surface located on one side in a thickness direction and a second surface located on the other side in the thickness direction, the louver adjusting a blowing-out direction of air blown out from the air outlet, wherein a peak of a blade thickness is present in a region on a leading edge side in the louver, the blade thickness in the region on the leading edge side gradually increases from the leading edge toward a position of the peak of the blade thickness and gradually decreases from the position of the peak of the blade thickness toward a trailing edge side of the louver, wherein on the second surface of the louver, a plurality of grooves recessed toward the first surface side and extending in a direction crossing an air flow direction are provided side-by-side in the air flow direction, characterized in that: a peak of a groove depth (d) in the plurality of grooves is present in the region on the leading edge side in the louver, the groove depths (d) in the plurality of grooves gradually increase from the leading edge side toward a position of the peak of the groove depth (d) and gradually decrease from the position of the peak of the groove depth (d) toward the trailing edge side, and the position of the peak of the groove depth (d) is provided in a region corresponding to the position of the peak of the blade thickness. a casing including an air outlet; and a louver including a first surface located on one side in a thickness direction and a second surface located on the other side in the thickness direction, the louver adjusting a blowing-out direction of air blown out from the air outlet, wherein a peak of a blade thickness is present in a region on a leading edge side in the louver, the blade thickness in the region on the leading edge side gradually increases from the leading edge toward a position of the peak of the blade thickness and gradually decreases from the position of the peak of the blade thickness toward a trailing edge side of the louver, wherein on the second surface of the louver, a plurality of grooves recessed toward the first surface side and extending in a direction crossing an air flow direction are provided side-by-side in the air flow direction, characterized in that: a peak of a groove depth (d) in the plurality of grooves is present in the region on the leading edge side in the louver, the groove depths (d) in the plurality of grooves gradually increase from the leading edge side toward a position of the peak of the groove depth (d) and gradually decrease from the position of the peak of the groove depth (d) toward the trailing edge side, and the position of the peak of the groove depth (d) is provided in a region corresponding to the position of the peak of the blade thickness. a peak of a groove depth (d) in the plurality of grooves is present in the region on the leading edge side in the louver, the groove depths (d) in the plurality of grooves gradually increase from the leading edge side toward a position of the peak of the groove depth (d) and gradually decrease from the position of the peak of the groove depth (d) toward the trailing edge side, and the position of the peak of the groove depth (d) is provided in a region corresponding to the position of the peak of the blade thickness.