This paper presents the relation between sinusoidal vibration or damped vibration of visual display terminal and its indistinctness as evaluation index, which is fundamental knowledges to establish the method for evaluating floor vibration. First, we made a testing device composed of a table on which CRT could vibrate and a table on which CRT could stand still. Next, using this testing device, we made a sensory scale about indistinctness of vibrating CRT by the sensory test. Finally, we picked up a physical quantity corresponded to the sensory scale, and presented the relation between them as the evaluation index.
