A polyamide resin in which an average particle size of individual crystals measured by a small-angle X-ray scattering apparatus is 8.0 nm or less, wherein the average particle size of the individual crystals is measured through an analytical equipment by fitting a scattering pattern obtained by irradiating X-rays with energies of 10 KeV to 20 KeV in the small-angle X-ray scattering apparatus to a solid sphere model and as further described in the specification, and the individual crystals having the average particle size of 8.0 nm or less comprises a first polyamide segment including a repeating unit represented by the following Chemical Formula 1, or a block comprised thereof: in Chemical Formula 1, Ar 1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms, and amorphous polymer chains present between the individual crystals having the average particle size of 8.0 nm or less including the first polyamide segment including the repeating unit represented by Chemical Formula 1 or the block composed thereof comprise a second polyamide segment including a repeating unit represented by the following Chemical formula 2, or a block composed thereof: in Chemical Formula 2, Ar 2 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms, and based on the total repeating units contained in the polyamide resin, the content of the repeating units represented by Chemical Formula 1 is 60 mol% to 95 mol%, and the content of the repeating units represented by Chemical Formula 2 is 5 mol% to 40 mol%. the average particle size of the individual crystals is measured through an analytical equipment by fitting a scattering pattern obtained by irradiating X-rays with energies of 10 KeV to 20 KeV in the small-angle X-ray scattering apparatus to a solid sphere model and as further described in the specification, and the individual crystals having the average particle size of 8.0 nm or less comprises a first polyamide segment including a repeating unit represented by the following Chemical Formula 1, or a block comprised thereof: in Chemical Formula 1, Ar 1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms, and amorphous polymer chains present between the individual crystals having the average particle size of 8.0 nm or less including the first polyamide segment including the repeating unit represented by Chemical Formula 1 or the block composed thereof comprise a second polyamide segment including a repeating unit represented by the following Chemical formula 2, or a block composed thereof: in Chemical Formula 2, Ar 2 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms, and based on the total repeating units contained in the polyamide resin, the content of the repeating units represented by Chemical Formula 1 is 60 mol% to 95 mol%, and the content of the repeating units represented by Chemical Formula 2 is 5 mol% to 40 mol%.