Trichoderma sp. SY most effectively produces an extracellular ${gamma}$-L-arabinofuranosidase (AF) using arabinose as a carbon source. AF grown on cellulose as a carbon source was purified 28-fold with 4.4% yield by DEAE exchange and HQ/20 cation exchange chromatographies The purified enzyme was found to be homogeneous on SDS-PAGE with molecular weight of 89 kDa. It exhibited a high level of activity with p-nitrophenyl ${alpha}$-L-arabinofuranoside, showing $K_m$ and $V_{max}$ values of $0.15;{mu}M$ and $239.85U{cdot}mg^{-1}$, respectively and did not require any metal ion for activity. It also released p-nitrophenol from p-nitrophenol conjugated ${eta}$-D-xylopyranoside, and ${eta}$-D-galactopyranoside not from ${eta}$-D-glucopyranoside.