We demonstrate a p$-wave optical Feshbach resonance (OFR) using purely long-range molecular states of a fermionic isotope of ytterbium ^{171}Yb, following the proposition made by K. Goyal et al. [Phys. Rev. A 82, 062704 (2010)]. The p-wave OFR is clearly observed as a modification of a photoassociation rate for atomic ensembles at about 5 micro-Kelvins. A scattering phase shift variation of delta eta=0.022 rad is observed with an atom loss rate coefficient K=28.0*10^{-12} cm^3/s.