To provide an apparatus for estimating structural performance indicators and a method of performing real-time monitoring of structural performance of a structure allowing the estimation of an attenuation coefficient and rigidity in each layer of a structure through on-line processing, in real time.

In a first process, a sensor 3a of a measuring instrument 3 is installed in a predetermined position in each layer of the structure 7. In a second process, absolute acceleration, which is observed by inputting fundamental acceleration into the structure 7 using the measuring instrument 3, is measured, and is directly transmitted to an apparatus main body for estimating structural performance indicators 2. In a third process, calculations are performed in the apparatus main body 2 to estimate the attenuation coefficient and rigidity in each layer of the structure 7. In a fourth process, the second process and the third process are repeated every time the absolute acceleration is observed to acquire estimate values of the attenuation coefficient and rigidity in each layer of the structure 7 in a time series. Structural performance is monitored using them as indicators.