A multi-blade fan comprising: a support body that rotates about a rotary shaft; and a plurality of blades (100, 101-135) secured to the support body such that an inter-blade pitch angle (θ k) relative to the rotary shaft assumes a prescribed arrangement, the blade pitch angle arrangement being given by the following formula θ k = θ 0 + ∑ m − 1 M α m • sin 2 π mk Z + β m k = 1, Λ, Z, M = Z 2 where Z is even M = Z − 1 2 where Z is odd In the formula, Z is a natural number equal to or greater than 6; k = 1, Λ, Z (where k is a natural number); m = 1, Λ, M (where m is a natural number); θ k = arrangement of each of the inter-blade pitch angles (degree); θ 0 = 360 Z (angle in the case of equal-interval pitches) (degree); α m = amplitude value of sine functions of order m; and β m = phase shift of sine functions of order m., the blades extending along an axial direction of the rotary shaft, the plurality of blades being disposed such that, with respect to amplitude values of periodic functions at individual orders when the prescribed arrangement is expanded in a periodic Fourier series, a maximum amplitude value (α max) is less than 200% of a second-largest amplitude value (α 2nd), wherein the plurality of blades are disposed such that, with respect to the amplitude values of periodic functions at individual orders of the periodic Fourier series, the second-largest amplitude value (α 2nd) is equal to or less than 100% of the maximum amplitude value (α max) and the third-largest amplitude value (α 3rd) is within a range of 50-100% of the maximum amplitude value (α max), wherein the plurality of blades are disposed such that a selection is made from lower orders where the order of a periodic function (m) that has an amplitude value within a range of 50-100% of the maximum amplitude value (α max) is two or greater, whereby the plurality of blades are disposed such that the amplitude values of periodic functions at a number of orders (m) equal to or greater than one-half of the total number of orders of the periodic Fourier series are within a range of 50-100% of the maximum amplitude value (α max). a support body that rotates about a rotary shaft; and a plurality of blades (100, 101-135) secured to the support body such that an inter-blade pitch angle (θ k) relative to the rotary shaft assumes a prescribed arrangement, the blade pitch angle arrangement being given by the following formula θ k = θ 0 + ∑ m − 1 M α m • sin 2 π mk Z + β m k = 1, Λ, Z, M = Z 2 where Z is even M = Z − 1 2 where Z is odd In the formula, Z is a natural number equal to or greater than 6; k = 1, Λ, Z (where k is a natural number); m = 1, Λ, M (where m is a natural number); θ k = arrangement of each of the inter-blade pitch angles (degree); θ 0 = 360 Z (angle in the case of equal-interval pitches) (degree); α m = amplitude value of sine functions of order m; and β m = phase shift of sine functions of order m. k = 1, Λ, Z (where k is a natural number); m = 1, Λ, M (where m is a natural number); θ k = arrangement of each of the inter-blade pitch angles (degree); θ 0 = 360 Z (angle in the case of equal-interval pitches) (degree); α m = amplitude value of sine functions of order m; and β m = phase shift of sine functions of order m., the blades extending along an axial direction of the rotary shaft, the plurality of blades being disposed such that, with respect to amplitude values of periodic functions at individual orders when the prescribed arrangement is expanded in a periodic Fourier series, a maximum amplitude value (α max) is less than 200% of a second-largest amplitude value (α 2nd), wherein the plurality of blades are disposed such that, with respect to the amplitude values of periodic functions at individual orders of the periodic Fourier series, the second-largest amplitude value (α 2nd) is equal to or less than 100% of the maximum amplitude value (α max) and the third-largest amplitude value (α 3rd) is within a range of 50-100% of the maximum amplitude value (α max), wherein the plurality of blades are disposed such that a selection is made from lower orders where the order of a periodic function (m) that has an amplitude value within a range of 50-100% of the maximum amplitude value (α max) is two or greater, whereby the plurality of blades are disposed such that the amplitude values of periodic functions at a number of orders (m) equal to or greater than one-half of the total number of orders of the periodic Fourier series are within a range of 50-100% of the maximum amplitude value (α max).