PURPOSE: To make it possible to obtain the vibration restricting sructure of an optimum wall body by measuring simultaneously phase differences and vibration characteristics among measuring points of the vibration system, which receives forced vibration from the external, at respective measuring points and analyzing vibration in the system and obtaining analysis data repeatedly.

CONSTITUTION: A vibration frequency is inputted from oscillator 8 to vibromotive machine 7. Acceleration response from pickup 11 provided at each of measuring points C-1, C-3 and C-5 set in tested object 1 is inputted to vibrometers 13a and 13b. Next, it is recorded on vibration level coders 14a to 14f according to vibration number, and the acceleration response at each measuring point is transmitted to channel CH1 of synchroscope 16 with time difference by remote controller 15. Meanwhile, the acceleration response is transmitted to channel CH2 through vibrometer 13b. Then, the time base of synchroscope 16 is adjusted, and the time difference between channels CH1 and CH2 is read from the scale of the vibration waveform of an oscillograph, etc., and is converted to a phase difference. Consequently, the phase at each measuring point is recorded simultaneously together with the acceleration response, and correleration between them and the phase difference can be obtained.