Single crystals of a new compound Nb5Sn2Ga were obtained by the flux method using molten tin as a solvent. The crystal structure represents a tetragonal symmetry, space group D184hI4/mcm, ordered W5Si3-type structure. Lattice parameters are a=1.0586(2) nm and c=0.5177(1) nm. According to XPS study, the peaks of Nb, Sn and Ga 3dXP spectra negatively shift when the three elements of Nb, Sn and Ga form the compound of Nb5Sn2Ga. The compound shows superconductivity at Tc=1.75 K and ΔTc=140 mK. The residual resistivity ratio, RRR=ρ (293 K)/p (4.2 K), is 12. The Micro-Vickers hardness (MVH) value for the (100) or (110) face is 8.9-8.5 GPa, and for the (001) face is 10.1-9.1 GPa. Oxidation of the Nb5Sn2Ga starts at 562°C. Weight gain of the compound heated up to 1200°C in air is 37.3%. Final oxidation product contains NbO2, Nb2O5, Nb12O29, SnO2 and Ga2O3.