An axial fan comprising: - a hub ; - a plurality of blades arranged in a circumferential direction of the hub; - a cutout in a rear edge part of each of the plurality of blades, the rear edge part being opposite to a front edge part of the each of the plurality of blades in a rotational direction of the each of the plurality of blades, the cutout extending from the rear edge part toward the front edge part such that the cutout divides the rear edge part into an outer rear edge part and an inner rear edge part ; - a first thickness-increased part in a blade surface of the each of the plurality of blades, the first thickness-increased part being closer to the front edge part than a tangent line (L2) is, the tangent line (L2) extending through a rotational center (O) of the hub and being in contact with a valley part of the cutout , the valley part being closer to the front edge part than any other parts of the cutout, the first thickness-increased part extending from an inner circumference of the each of the plurality of blades toward an outer circumference of the each of the plurality of blades; - a first thickness-reduced part being adjacent to a part of the first thickness-increased part , the part being closer to the front edge part , the each of the plurality of blades being thinned in the first thickness-reduced part ; and - a second thickness-reduced part being positioned to overlap the tangent line (L2) and adjacent to a part of the first thickness-increased part , the part being closer to the rear edge part , the each of the plurality of blades being thinned in the second thickness-reduced part . - a hub ; - a plurality of blades arranged in a circumferential direction of the hub; - a cutout in a rear edge part of each of the plurality of blades, the rear edge part being opposite to a front edge part of the each of the plurality of blades in a rotational direction of the each of the plurality of blades, the cutout extending from the rear edge part toward the front edge part such that the cutout divides the rear edge part into an outer rear edge part and an inner rear edge part ; - a first thickness-increased part in a blade surface of the each of the plurality of blades, the first thickness-increased part being closer to the front edge part than a tangent line (L2) is, the tangent line (L2) extending through a rotational center (O) of the hub and being in contact with a valley part of the cutout , the valley part being closer to the front edge part than any other parts of the cutout, the first thickness-increased part extending from an inner circumference of the each of the plurality of blades toward an outer circumference of the each of the plurality of blades; - a first thickness-reduced part being adjacent to a part of the first thickness-increased part , the part being closer to the front edge part , the each of the plurality of blades being thinned in the first thickness-reduced part ; and - a second thickness-reduced part being positioned to overlap the tangent line (L2) and adjacent to a part of the first thickness-increased part , the part being closer to the rear edge part , the each of the plurality of blades being thinned in the second thickness-reduced part . <EOS>