The even-parity autoionizing resonance series 3p^5np′[3/2]1,2, 3p^5np′[1/2] 1, and 3p^5nf′[5/2]3 of Ar have been investigated exciting from the two metastable states 3p^54s[3/2]2 and 3p^54s′[1/2]0 in the photon energy range of 32500-35600 cm^-1 with an experimental band- width of ～0.1 cm^-1. The excitation spectra of the even-parity autoionizing resonance series show typical asymmetric line shapes. New level energies, quantum defects, line profile index and resonance widths, resonance lifetime and reduced widths of the autoionizing resonances are derived by a Fano-type line-shape analysis. The line profile index q and the resonance widths F are shown to be approximately proportional to the effective principal quantum number n^＊. The line separation of the 3p^5np′ autoionizing resonances is discussed.
