There is provided a state-monitory system of a moving apparatus which is capable of deducing an abnormality and cause of breakdown of the moving apparatus by Equationematical analysis only by measuring vibration of a casing or object to be monitored and which requires no large-scaled apparatus.An equivalent model of the moving apparatus 1 is formed, which is adapted to replace the vibration of a monitored object of the moving apparatus 1 with the vibration of a viscoelastic member such as an elastic spring etc. and which is adapted to be capable of outputting virtual vibration data having synthesized vibration equivalent to the vibration of the viscoelastic member, and the equivalent model is Equationematically analyzed, thereby estimating the abnormality and cause of breakdown of the moving apparatus 1 only by measuring vibration of the casing 8 or a monitored object.