Piezoelectric materials are one of the functional materials which convert the energy of stress to electric energy and widely used for sensors. Up to now, many materials were investigated for this application. Among them, LTGA (La3Ta0.5Ga5.3Al0.2O14) and SNGS (Sr3NbGa3Si2O14) single crystals have langasite type structures and they are famous for their piezoelectric characteristics even in high temperature more than 1,000 degrees [1]. Recently, we studied optical properties such as photoluminescence (PL) and radioluminescence (RL, scintillation in other words) of other langasite crystals including Ca3NbGa3Si2O14 (CNGS), La3Ga5SiO14 (LGS), La3Nb0.5Ga5.3Al0.2O14 (LNGA), and LTGA [2, 3]. In previous studies, we found that these langasite crystals exhibited quite interesting feature of very fast sub-ns decay time in visible wavelength and detectable scintillation signal [2, 3]. Therefore it was proved that langasite crystals can be potentially applicable for scintillator applications. In this work, optical and scintillation properties of Sr3NbGa3Si2O14 (SNGS) single crystal were evaluated for the first time, and compared with those properties of La3Ta0.5Ga5.3Al0.2O14 (LTGA) which was previously reported. Although these materials are a type of piezoelectric materials, significant optical and scintillation properties were observed. SNGS showed ~80% optical transmittance in wavelength longer than 250 nm. Under 250 nm excitation, strong photoluminescence appeared at 400 nm with a primary decay time of 1.4 ns. In X-ray induced radioluminescence spectrum, intense emission peak at 400 nm was observed and primary scintillation decay time resulted ~ 1.37 ms. Finally, the absolute scintillation light yield of SNGS turned out to be 850 photons/MeV under 137Cs 662 keV gamma-ray excitation and it was largely brighter than LTGA.[1] I.H. Jung, K.H.Auh, Mater. Lett., 51 (2001) 129. [2] Y. Futami, T. Yanagida, Y. Fujimoto, V. Jary, J. Pejchal, Y. Yokota, M. Kikuchi, M. Nikl, A. Yoshikawa: Opt. Mater., 34 (2012) 1513. [3] Y. Futami, Y.Yokota, M. Sato, T. Yanagida, N. Kawaguchi, Y. Fujimoto, K. Tota, K. Onodera, A.Yoshikawa, J. Cryst. Growth, 352 (2012) 129.