A measurement system comprising: a plurality of measurement devices configured to perform measurements at a plurality of sites in a measurement target, respectively; and a measurement management apparatus comprising: a synchronization time transmitter configured to transmit common time information to each of the plurality of measurement devices in the measurement target; a measured data acquirer configured to acquire a plurality of measured data from the plurality of measurement devices via a communication network, times timed by the measurement devices being correlated with each other based on the common time information and the plurality of measured data being measured by the measurement devices based on the correlated time, the measurement times of the plurality of measured data being correlated with each other; and an estimator configured to correlate the plurality of measured data acquired by the measured data acquirer based on the common time information and to determine whether abnormality is occurring and a site of abnormality occurrence in the measurement target; wherein each of the measurement devices is configured to transmit the measured data measured based on the correlated time to the measurement management apparatus. a plurality of measurement devices configured to perform measurements at a plurality of sites in a measurement target, respectively; and a measurement management apparatus comprising: a synchronization time transmitter configured to transmit common time information to each of the plurality of measurement devices in the measurement target; a measured data acquirer configured to acquire a plurality of measured data from the plurality of measurement devices via a communication network, times timed by the measurement devices being correlated with each other based on the common time information and the plurality of measured data being measured by the measurement devices based on the correlated time, the measurement times of the plurality of measured data being correlated with each other; and an estimator configured to correlate the plurality of measured data acquired by the measured data acquirer based on the common time information and to determine whether abnormality is occurring and a site of abnormality occurrence in the measurement target; wherein each of the measurement devices is configured to transmit the measured data measured based on the correlated time to the measurement management apparatus. a synchronization time transmitter configured to transmit common time information to each of the plurality of measurement devices in the measurement target; a measured data acquirer configured to acquire a plurality of measured data from the plurality of measurement devices via a communication network, times timed by the measurement devices being correlated with each other based on the common time information and the plurality of measured data being measured by the measurement devices based on the correlated time, the measurement times of the plurality of measured data being correlated with each other; and an estimator configured to correlate the plurality of measured data acquired by the measured data acquirer based on the common time information and to determine whether abnormality is occurring and a site of abnormality occurrence in the measurement target; wherein each of the measurement devices is configured to transmit the measured data measured based on the correlated time to the measurement management apparatus.