SOWAN is instruments for the ultrasonic wave velocity measurement of rock samples. It is possible to read P and S wave propagation time with high accuracy, because it contains high voltage (500V) pulse and pulse width 1 ns. This instrument is for non-destructive test to obtain elastic properties of rock. By the input of length and density of rock, then it can calculate dynamic poisson�s ratio, shear modulus, young modulus etc. This instrument is useful for civil engineering and rock mechanic for rock-strength analysis and also geophysicist at oil company for rock physics analysis.