PURPOSE: To improve the accuracy of dynamic characteristic measurement by energizing a hammer tip with an electromagnet and providing a second hammering preventing mechanism thereby controlling the contact time for determining exciting force and an excitation frequency band and eliminating the second hammering.

CONSTITUTION: A pistol-like frame 6 built in with an impact exciter has a grip part 6a in the lower part and a fixing plate 6b in the upper part. When the switch 27 of the part 6a is pushed, electric current flows in a lead wire 28, and the coil 14 of an electromagnet is driven by the voltage generated by a controller 13 regulated by a voltage regulating knob 12. As the coil 14 is driven, a driving rod 16 supported to the frame 6 by a pin 15 is driven like pulses, and the driving force thereof is transmitted to a hammer 7 through a push rod 18 provided in a guide 17. A force detector 9 is provided to the leading end of the hammer 7, and a hammer tip 10 permitting controlling contact time is mounted to the end thereof. The second hammering is prevented by a spring 25 installed by way of a space adjusting bushing 26 from the hammer 7.