A signal recording system and signal recorder including a status recognizing method and a status recognizing function of recording feature parameters reflecting the status change and a raw signal for status monitoring with no wasteful recording media. Feature parameters in the high, intermediate, and low frequency ranges of a signal generated from a sensor are determined by calculation, and whether either only the feature parameter or both the feature parameters and a raw signal of a necessary time length are recorded is decided depending on the degree of a status change. In judging the status, the recorded feature parameters are converted normalized feature parameters conforming to a normal probability density distribution, the status judgment criterion of dimensional/dimensionless feature parameters and normalized feature parameters are determined according to probability examination, confidence interval, and possibility theory, and the results of judgment of the dimensional/dimensionless feature parameters are united, thereby making status judgment. As required, the tendency of status change is managed, the status is predicted, and the cause of a status change is analyzed. The status at the measurement is displayed and a warning is issued if the status is dangerous.