PURPOSE: To exactly check sensitivity with a simple operation by applying the oscillation of a prescribed level to a calibration plate having a prescribed attenuation constant and outputting wave reception levels by reception side AE sensors provided at prescribed spaced intervals.

CONSTITUTION: A transmission side AE sensor 11 mounted to the prescribed position on the surface of the calibration plate 12 resonates when the electric impulse signal generated by an electric impulse signal generator 10 is inputted thereto. The elastic waves generated by solid oscillation are propagated to the calibration plate 12. The reception side AE sensors 13 mounted to an arbitrary position of the calibration plate 12 receive the elastic waves propagating in the calibration plate 12 and convert the waves to an AE signal. The reception sensitivity is thus checked. The AE signals from the sensor 13 are amplified 14 and are outputted to an output part 14a constituted of a digital display plate and a printer which prints and outputs the display contents. This signal level is attenuated by propagation to the level lower than the level at the point of the time when the waves are transmitted but the calibration plate 12 has the prescribed attenuation constant and, therefore, the output level of the sensors 13 are obtd. at approximately the same level by installing the plural sensors 13 to the same position.