To solve the problem wherein, when a vibration device using a conventional magnetostrictor is applied to a testing device, vibration can be applied only to one-axis direction in three-axis directions, and thereby it is unsuitable to be used as a vibration testing device.

In this triaxial vibration testing device, a vibrator of a Z-axis magnetostrictive actuator 5 is connected to the bottom surface of a material stand 1 through a slide guide 8 uninfluenced by vibration having a vibration direction different from that of the actuator, and vibrators of an X-axis magnetostrictive actuator 3 and a Y-axis magnetostrictive actuator 4 are connected to each orthogonal side face of the material stand in the same way, to thereby perform excitation with the material stand uninfluenced by vibration from another actuator.