A series of triaxial tests were performed on specimens made of Toyoura sand having different dry densities. Very small unloading/ reloading cycles were applied to obtain “static” Young’s modulus. Furthermore, as the “dynamic” measurements, two types of wave propagation techniques were applied; one using Bender elements, and the other one using piezoelectric actuators to excite primary and secondary waves. Based on these static and dynamic measurements, we discuss the following aspects: 1) the difference among the three types of dynamic measurements, 2) the relationships between the dynamic and static measurement results and 3) the effects of stress stateinduced anisotropy and dry densities of the specimens.