A railway axle comprising: a pair of fitting portions each of which is a column having a diameter D W, for a railway wheel to be press-fitted thereon; and a center parallel portion disposed between the pair of fitting portions, the center parallel portion being a column having a diameter D A which is smaller than the diameter D W, wherein the fitting portion includes an inner end (2 IN) disposed closer to the center parallel portion in a direction of a center axis of the railway axle than a center position of the fitting portion, an outer end (2 OU) disposed farther from the center parallel portion in the direction of the center axis of the railway axle than the center position of the fitting portion, a fitting portion hardened layer formed in an outer layer of the fitting portion, and a base metal portion disposed inward of the fitting portion hardened layer, the center parallel portion includes a center parallel portion hardened layer formed in an outer layer of the center parallel portion, and the base metal portion disposed inward of the center parallel portion hardened layer, a chemical composition of the base metal portion consists of, in mass%, C: 0.30 to 0.42%, Si: 0.10 to 0.50%, Mn: 0.40 to 1.20%, P: 0.020% or less, S: 0.040% or less, N: 0.0200% or less, O: 0.0040% or less, Ca: 0 to 0.0010%, Cr: 0 to 0.30%, Mo: 0 to 0.10%, Cu: 0 to 0.30%, Ni: 0 to 0.30%, Al: 0 to 0.100%, V: 0 to 0.060%, Ti: 0 to 0.020%, Nb: 0 to 0.030%, B: 0 to 0.0050%, and the balance being Fe and impurities, D W /D A which is a ratio of the diameter D W of the fitting portion to the diameter D A of the center parallel portion is 1.10 to 1.30, a depth Cw of the fitting portion hardened layer at a position 5 mm away from the inner end (2 IN) toward the outer end of the fitting portion in the direction of the center axis is 2.5 mm to 0.10×D W mm, and C W /C A which is a ratio of the depth Cw of the fitting portion hardened layer to a depth C A of the center parallel portion hardened layer is 0.34 to 0.93, wherein the depth Cw of the fitting portion hardened layer and the depth C A of the center parallel portion hardened layer refer to a distance (mm) in the radial direction from the surface of the respective portion to the position of limit hardness as defined in JIS G 0559, wherein the limit hardness is 400 HV in terms of Vickers hardness tested in accordance with JIS Z 2244. a pair of fitting portions each of which is a column having a diameter D W, for a railway wheel to be press-fitted thereon; and a center parallel portion disposed between the pair of fitting portions, the center parallel portion being a column having a diameter D A which is smaller than the diameter D W, wherein the fitting portion includes an inner end (2 IN) disposed closer to the center parallel portion in a direction of a center axis of the railway axle than a center position of the fitting portion, an outer end (2 OU) disposed farther from the center parallel portion in the direction of the center axis of the railway axle than the center position of the fitting portion, a fitting portion hardened layer formed in an outer layer of the fitting portion, and a base metal portion disposed inward of the fitting portion hardened layer, an inner end (2 IN) disposed closer to the center parallel portion in a direction of a center axis of the railway axle than a center position of the fitting portion, an outer end (2 OU) disposed farther from the center parallel portion in the direction of the center axis of the railway axle than the center position of the fitting portion, a fitting portion hardened layer formed in an outer layer of the fitting portion, and a base metal portion disposed inward of the fitting portion hardened layer, the center parallel portion includes a center parallel portion hardened layer formed in an outer layer of the center parallel portion, and the base metal portion disposed inward of the center parallel portion hardened layer, a center parallel portion hardened layer formed in an outer layer of the center parallel portion, and the base metal portion disposed inward of the center parallel portion hardened layer, a chemical composition of the base metal portion consists of, in mass%, C: 0.30 to 0.42%, Si: 0.10 to 0.50%, Mn: 0.40 to 1.20%, P: 0.020% or less, S: 0.040% or less, N: 0.0200% or less, O: 0.0040% or less, Ca: 0 to 0.0010%, Cr: 0 to 0.30%, Mo: 0 to 0.10%, Cu: 0 to 0.30%, Ni: 0 to 0.30%, Al: 0 to 0.100%, V: 0 to 0.060%, Ti: 0 to 0.020%, Nb: 0 to 0.030%, B: 0 to 0.0050%, and the balance being Fe and impurities, D W /D A which is a ratio of the diameter D W of the fitting portion to the diameter D A of the center parallel portion is 1.10 to 1.30, a depth Cw of the fitting portion hardened layer at a position 5 mm away from the inner end (2 IN) toward the outer end of the fitting portion in the direction of the center axis is 2.5 mm to 0.10×D W mm, and C W /C A which is a ratio of the depth Cw of the fitting portion hardened layer to a depth C A of the center parallel portion hardened layer is 0.34 to 0.93, wherein the depth Cw of the fitting portion hardened layer and the depth C A of the center parallel portion hardened layer refer to a distance (mm) in the radial direction from the surface of the respective portion to the position of limit hardness as defined in JIS G 0559, wherein the limit hardness is 400 HV in terms of Vickers hardness tested in accordance with JIS Z 2244.